Furahan Biology and Allied Matters

The eyes have it!

2012-01-22T17:14:00.012+01:00

I guess almost everyone who designs fictive alien life forms want them to look truly 'alien': you want your animal to have something that tells the viewer that this is an original; it should look unearthly and yet as if it ought to look that way. The word 'alienness' is perhaps grammatically correct, but lacks punch; something like 'alienosity' might do the trick...

Frivolity aside, striking a balance between oddity and plausibility is difficult. Darwinian evolution tends towards optimisation, which in reality means the optimal balance between function and cost; economy of design pervades everything in biological evolution. As evolution on Earth has been following that path for quite some time, it is not easy to come up with strikingly different designs that work at least as well as familiar ones.

Doing away with eyes is such a major departure from 'earth standard', increasing alienosity significantly. Imagine sightless animals with otherwordly senses, pinging your innards with sonar or recognising you by the thermal pattern of your warm throat, your cold nose and old hair. Yes, sightlessness fits the bill nicely. But can you do away with eyes? I think not, except under very special circumstances. I will try to discuss why 'the eyes have it', and this will probably need more than one post. The present one will deal with probably the most famous sightless speculative world: Darwin IV by Wayne Douglas Barlowe.

Pronghead from 'Expedition';click to enlarge
Copyright 1990 Wayne Douglas Barlowe

Let me start by stating my admiration for Mr Barlowe's painting skills. The pronghead, show above, works great against the background, and the fact that is half lit works compositionally and also highlights the luminescent spots nicely. I have said it before: I wish I could paint as well. Darwin IV is presented in his book 'Expedition', available from Amazon. A television documentary with computer generated graphics is available as well.

'Eosapien' (fragment from larger painting).
Copyright 1990 Wayne Douglas Barlowe

The picture here shows some ballooning animals floating away in the darkness (they are called 'eosapien', but I suspect that that is a mistake, as the 's' in 'sapiens' does not indicate a plural). The luminescent spots are well visible on these animals as well as on animals in the distance. Perhaps the latter ought to be less conspicuous, seeing that the eosapiens are predators.

There is an explanation in the beginning of the book 'expedition' explaining why animals there have no eyes. The idea is that the planet was covered in thick fog for very long periods, so that vision as we know it was pretty useless during that time. Animals accordingly developed other senses: apparently there is a pressure-sensitive lateral line system, but not much is known about it. Also stated are the ability to use sonar and infrared, and the latter one is the subject of this post. The infrared sense is apparently located in 'tiny infrared receptor pits'. When the atmosphere cleared up later, these alternate senses were so well developed and entrenched that vision did not have much chance: the first stages of eyes would be poor, and would not convey an appreciable advantage to their owners, so their evolution never got under way. As defences go, this is an ingenious one. I doubt eye evolution would really be held back by superior senses, already present, but that line of thought deserves further thought.

First, let's discuss the heat sense, one of Darwin IV's ways of making sense of the environment. Many of Barlowe's animals have intriguing dots and stripes in glorious colours, glowing in the dark. Now bioluminescence was a brilliant idea with a high alienosity index ( I wish I had thought of that in time). However, it is rather odd for animals to have organs that produce light when there is nothing around to see that light. At first sense offering light to the blind seems a serious mistake, but the text again shows that this critique has been foreseen. It states that these 'biolights' are 'heat-radiating bioluminous spots that appear quite vivid to infrared sensors'. In effect, this means that the production of light is a side effect of the production of heat.

Electromagnetic spectrum from Wikipedia

Here we need to call attention to the electromagnetic spectrum. You may remember that the part humans can see is flanked by ultraviolet on the high frequency side and by infrared on the low frequency side. Now infrared is divided into near infrared and far infrared. Near infrared is in effect another colour, one humans simply cannot see, but which does not represent heat as such (here is a nice photography site explaining it well).

Left, visible light, right near infrared; Click to enlarge
Images from http://dpfwiw.com/ir.htm

There are many images on the internet taken in the near infrared range, 'translated' to activity in the part of the spectrum we can see (a true infrared image is useless, as we wouldn't even see that there was an image!). Many images of woods and trees show that leaves are very bright in the near infrared range, but that does not mean they are warm. They are not; they simply reflect a lot of the near infrared radiation falling on them, coming from the sun (the sun shines brightly in the near infrared range). Remember that a green leaf looks green because it reflects more green light than it does light of other colours. By the way, the images above show that near infrared travels better through haze and fog than visible light does, so having fog as part of the 'anti-eye argument' has its merits.

But do the animals of Darwin IV make use of near infrared? The text states that we are dealing with detection of heat, and that means 'far infrared'. Then again, most objects radiating heat also radiate near infrared radiation, so you could use one for the other. But I will assume true heat detection.

The heat organs on the bodies of Darwin IV's animal also produce visible light. That is not surprising: any fire produces heat as well as light, and often both effects are welcome (come to think of it, a fire that produced heat but not visible light would be pretty dangerous). Light bulbs are only meant to produce light, but are spectacularly inefficient in this respect: most of the power they consume goes into the generation of heat rather than of light. Nature, however, has managed to produce light without heat in the form of bioluminescence. That separation holds on Earth, though. On Darwin IV, you would expect evolution to be faced with the challenge of producing heat as efficiently as possible, meaning without squandering resources such as producing visible light as a side effect. Apparently evolution failed in this respect. This seems rather unlikely, as there must be metabolic ways to produce just heat but not light in a controlled manner. Our own bodies radiate heat but not light, so I do not think that bioluminescence as a by-product of heat production is very convincing.

But the production side of heat signals is not my major concern; that resolves around the reception side: how do Barlowe's animals make sense of the heat signature of other animals? As usual, there are animals on Earth making use of heat detection; the pit viper is probably the most famous one***. This involves making sense of radiation in the far infrared range, something called 'thermography', or writing with heat. I have copied some images from Wikipedia below. There is a good discussion here as well.

Thermography of a cat from Wikipedia

The main point of these images is what they are: images! An image shows you what is where in space. The more pixels you have, the more information the image can carry. An image is made by a camera, and digital cameras have a receptive surface, and the image is focused on that surface by a lens. A cheap camera might have a poor lens, with an unsharp picture, and with a low number of pixels. When better quality is asked for, lenses get better and the number of pixels increases. The above, in a nutshell, is the evolution of the eye (well, not every eye resembles a camera, but many do). Man-made thermographic images show that the radiation of the far infrared basically follows the same principles as visible light does. You can bend rays with a lens, and you can detect them with dedicated sensors. That does not hold for all parts of the electromagnetic spectrum: it would be hard to detect X-rays as they easily pass through tissues, and it is extraordinarily hard to focus them. I would not be surprised at all to find that biological chemicals are better at bending radiation in the visible part of the spectrum than in the far infrared: water bends light. But the premise of Darwin IV was that animals there are able to detect heat, like the pit viper. In such snakes, heat detection still has poor spatial resolution, probably because their heat detecting organs have no lens in them. Suppose the animals of Darwin IV started out a long time in their past with some molecule that responded when subjected to far infrared radiation. Wouldn't evolution drive that organ to become ever better at telling where the radiation was coming from? That development would run exactly parallel to the evolution of the eye. 'Normal' eyes started out that way, and recent evolutionary theory holds that eyes developed many times, in many forms, and extremely quickly too. The ability to detect heat would probably also be subject to the same optimisation process that affected normal vision, so its product would be an eye. Sensitive to other parts of the spectrum than our eyes, but an eye nevertheless...

Archival scenes III: "Here I am, on the shores of Lake L'Ambique..."

2012-01-09T22:29:00.005+01:00

Unfortunately, real life, as it is called, at times requires considerable energy. Energy is a limited commodity and seems to consume creativity before it starts devouring other resources. In fact, I have toyed with the idea of closing this blog for a few months, with a note saying 'Away until I'm back' or something of equal intelligence.

But not yet. There is life here, and some unheard-of beasties may be encountered in the niches of the archival biotopes. I do not think I have ever shown much about humans on Furaha, which has its roots in my hesitation to even allow them on the planet. I thought they would wreck the place within several generations. After all, it's what they do. However, I decided that the project needed human interest, so I did introduce this alien species on my pristine planet. Once I got over my initial distrust of them, I did enjoy having humans around for various reasons: they could act as scale indicators, or they could be the actors in side stories about scientists arguing about animals' names and other typically human silliness.

But I never did a painting of humans on Furaha, and I do not think I ever will. There is a very rough sketch in the first ever post of this blog, and today I will present you with another sketch, only slightly less rough.

Click to enlarge; copyright Gert van Dijk

This is a pencil sketch on tracing paper, which explains why the contrast isn't that good. It also wasn't developed beyond this first approach (please do not look at the human's legs!).

As you can see, a Furahan citizen/scientist is squatting down near to a Furahan predator, a 'prober', to have a closer look at it. There is some kind of vehicle behind him; I tried to get away from the type of vehicle people might expect, and so designed a boring rectangle you could just dump anywhere as a temporary blot on the landscape. But this is about humans: apparently our hero is not afraid of the prober, which is not in line with some of the things I wrote over time. One statement held that, while humans may not be palatable to Furahan predators, the predators have not eaten enough humans yet to have learned this basic fact, so nothing keeps them from trying.

Let's assume that this person knows what he is doing. I certainly assumed so, as I modelled him on David Attenborough. The sketch probably never did resemble Mr Attenborough very much, but it did a bit more when I made it than it does now. I must hasten to say that I am a great admirer of Mr Attenborough, so this sketch was not at all meant to ridicule him. Quite the opposite, in fact. I think I was trying to imagine the very best of all possible documentaries on Furahan life. It would be one of those excellent BBC nature documentaries hosted by Attenborough. Imagine Attenborough on Furaha, with him talking straight into the camera. You will have to imagine the proper accent: "Well, here we are, on the shores of Lake L'Ambique, where we just happened to come upon this extraordinary animal..."

Furaha in NRC again, but in English this time!

2011-12-25T16:05:00.009+01:00

In June of this year, the Dutch newspaper NRC Handelsblad devoted a satisfyingly large section of their science section to the Furaha project. You will find the post on that subject here. As the text was in Dutch, the majority of the readers of this blog were unable to understand it. Mind you, I displayed the images at such a small scale to make it unreadable regardless of language; newspaper texts are not free, after all. But as time passes things change, so I asked Lucas Brouwers, the journalist who wrote the article, whether he would mind if I translated his text into English, and he in turn asked those in charge of such matters at the newspaper whether they would mind having the article republished in this form. The short answer was that no-one minded, so I went ahead and translated it into English. I tried to stay fairly close to the text, but at the same time wished to avoid the stilted style you often get in translations (it is much easier to write directly in a foreign language than it is to translate something from your own language into that language).

Click to enlarge; copyright NRC / Gert van Dijk

Hairy shufflers and radial flyers

BIOLOGY Professor of neurophysiology Gert van Dijk designs the flora and fauna of the fictive planet Furaha in his spare time.

Lucas Brouwers

At first glance the woolly-haired shuffler looks familiar. The animal looks quite a bit like a large mammal. It might just be a close relative of a rhinoceros, or a bison. But a closer look reveals that it is standing on six legs and that its upper jaw has grown into a grotesque shovel. Its more distant relatives are no less odd than the shuffler itself. There are six-legged predators, using their two front legs to knock their prey unconscious with. Or how about water animals, gliding solemnly through the oceans with hardly any moving parts visible from the outside. They are ingeniously designed: a hollow tube runs through their body, displacing water by pulsating continuously.

None of these animals are real. They are creations of Gert van Dijk, professor of neurophysiology in Leiden. In his spare time he designs the flora and fauna of the fictive planet Furaha, home to the woolly-haired shuffler. Van Dijk designed the workings of his planet in minute detail. From the evolution of life on Furaha to the place of the planet and its star in our galaxy: it is all there.

As a student Van Dijk used to paint extraterrestrial scenes for book covers for a publisher of what he now labels as "atrociously poor science fiction" The work did not make him exactly happy." That publisher asked me questions like the following: 'There is an empty corner in your painting; couldn't you fit in an exploding planet there?' ", he recollects.

Van Dijk therefore decided to start painting for his own pleasure. The first painting showing life on Furaha dates from 1979. It showed an exotic tree with an odd four-winged beast. That was only the beginning. Van Dijk: "Having painted a landscape with lots of grass in it, there obviously had to be something to eat all that grass. That was the start of the second painting. Well, once you have a animal eating plants, you are bound to need something to eat that animal in turn. That is how Furaha grew, and continued to grow."

A series of paintings followed. Later on Van Dijk started elaborating Furaha in other ways than using a painter's canvas. He writes essays on the biological background of his creations and simulates their anatomy using a computer. An astrophysics friend helped him to find a suitable spot in our galaxy for Furaha: in orbit around the star Nu Phoenicis IV. This star is of the same type as our sun and could therefore in principle support life.

Now, over thirty years after that first painting, the oceans and continents of Furaha are filled with life, there are detailed maps of the planet as well as descriptions of its climate. While there is a serious scientific background to the work, shaping the world flows from Van Dijk's fantasy.

This unusual hobby is known as 'speculative biology'. There aren't many speculative biologists. Van Dijk is familiar with most of the worlds they created. "There is the planet Nereus by Evan Black, there's Snaiad by Mehmet Kösemen and Epona, a collective project. There are a few projects dealing with the evolution of life on Earth in case the dinosaurs would not have gone extinct. That's largely it."

"There are certainly more people who wish to start a similar project", Van Dijk says, "but most do not combine a scientific background with artistic talent. Moreover, most projects stop after a few years' such as Snaiad, for the simple reason that they take up so much time. In fact, I stopped working on Furaha for years on end, but kept getting back to it. Fuaraha allows me to paint, write design and program. It meets to many of my needs to let it go."

Click to enlarge; copyright NRC / Gert van Dijk

How the woolly-haired shuffler came into being he no longer remembers in detail. "It's possible I had recently been looking at pictures of a rhinoceros. Things may just click together in my head. The inside of the skin folds of rhinos could well be covered in hairs, I may have thought."

That was the basic concept around which the animal took shape. "A skin fold covered in fur would be able to trap more warm air than one without hair. A fur coat, turned inside out, would have the same effect. That is in fact how the Inuit put their fur coats together", he explains. An animal with such furry folds would be able to deal with below-zero temperatures. And its shovel for a snout? "That evolved by itself".

In the end, Van Dijk painted the woolly-haired shuffler while it was upturning snow or soil in a search for plant roots or anything edible (see the cover). Its biology and ecology have been described in detail on Van Dijk's weblog. For instance, that says that the animal lives in small herds, and that that are small parasites living in the fur of its skin folds (trichophages).

Van Dijk does not use any fixed recipe to come up with a new life form. Sometime an animal crystallises around an interesting biological principle. The 'radial flyers', small creatures with four wings, came into being while he was sketching. Their wings are placed at an angle of 90 degrees to their body, like the blades of an helicopter rotor. The first sketches of these 'tetropters' showed a bilaterally symmetrical body , like a bird's, hanging under the wings. "That did not feel altogether right. I then thought it better to make the entire animal radially symmetrical, such as starfish or jellyfish."

In flight, the animals look a bit like helicopters as well. "Thanks to their design they have excellent manoeuvrability, but they aren't that fast in horizontal flight", Van Dijk explains. "The wings move in a figure eight-like pattern. A wing briefly beats against another one twice in every movement cycle. This creates additional lift". He explains calmly how this works. "Pigeons taking off do the same thing. Their two wings beat against one another above their backs. The contact between the wings does not only cause the characteristic sounds of pigeons taking off, but also causes extra air to be sucked in, and that generates an upwards force."

Van Dijk visualised the flight of these four-winged little creatures with computer simulations. The resulting flight of these radial flyers look looks organic. Their wings swing gracefully to and fro, rather like flags in the hands of a flagthrower. This mode of flight actually makes sense, as was proven by engineers a few years ago. With some pride Van Dijk wrote on his blog that they built a flying robot with four wings, flying in exactly the same manner as Furahan tetropters.

Another source of inspiration is nature on Earth. This is most apparent in those creation he labels as 'supercharged Earth designs'. One example of supercharging was his take on the undulating membranes of squids. "I started sketching animals with not two, but four of such membranes: two at the top and bottom, and two at the sides. From that design an animal emerged with a screw-like propulsion system."

There is no place on Furaha for unrealistic creatures. Ballonts, creatures that float by virtue of being lighter than air, may be struck from the record soon. Van Dijk: "I am beginning to think that balloon-like organism are not going to work. To keep them in I already increased the density of the atmosphere, but I do not really think that that is enough. That is a pity, because that would mean I have to abolish them."

No matter how exotic the Furahan fauna may be, most animals still look plausible and familiar. Why is that? Van Dijk: "That is an interesting question. Is the resemblance with life on Earth the result of a workable biomechanical design, or because many design models are simply prewired in my imagination?" He does not have the answer. One thing is certain, and that the resemblance is not introduced on purpose to make Furaha more palatable to his audience. Van Dijk: "I do not make any concessions to what people might like".

Making too many concessions is something he blames James Ccameron for, the director of the science fiction movie Avatar. Avarar takes place on the moon Pandora where there are six-legged animals, just like on Furaha. Wolves, horses and monkeys all have six-legged analogues on Pandora.

Van Dijk criticises their 'awkward' anatomy. "The horse analogues in Avatar have one pair of hind legs and two pairs of front legs, placed very close together. If you look carefully you will see that the two pairs of front legs move in synchrony. The designers simply doubled the front legs, so the animal looks in exactly the same way as a four-legged animal. At first glance they look cool, but essentially they are just horses with added frills."

The fact that Avatar is a science fiction movie is no excuse, Van Dijk thinks. "Of course, enjoying science fiction requires a degree of suspension of disbelief. But no-one ever claimed plausibility for the aliens of Star Wars or the sand worms of Dune, in contrast to what happened with Avatar. Cameron and scientists he hired claimed to have developed an accurate and biologically plausible world, and they simply did not.", Van Dijk says.

Obviously, Furaha reaches a fraction of the people of a Hollywood blockbuster. Van Dijk supposes that Furaha mainly attracts people with a higher education, interested, like he is, in what happens in the intersection of science and the arts. Still, he would definitely like to widen the readership of Furaha, for instance by publishing a book. In fact, he already posted a fake encyclopaedia of life on Furaha, including illustrations and infographics. He doesn't think there is a good chance of it getting published: "I do not know much about publishing books, but I guess that the market for such a work is very small."

You would expect professional biologists to be interested in a hobby that is so closely allied to their area of interest. Astrobiologists, dealing with the science of life on other planets, in particular might show an interest. But, apart from a rare exception, cross pollination between biologists and those working in speculative biology seems not to happen. Van Dijk: "They ought to like it in their heart of hearts. But perhaps astrobiologists do not wish to be associated with speculative biology. They are dealing with serious science and may prefer not to be to be portrayed as believers in little green men. Neither do I, by the way. I regard what I am doing as an intellectual and artistic game."

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Legends
- (Left bottom pen drawing) Furahan fish developed variable numbers of jaws and fins
- (Underneath the block of six paintings) Top row, from left to right: many-legged grouillards, honeysucker, mowers. Bottom row, from left to right: landscape, phleph and worryw. All images: copyright Gert van Dijk
- (Right top) Tetropters generate extra lift by clapping their wings together in the same way insects and pigeons do.
- (Far right) Tetropters are very manoeuvrable and can let themselves drop very quickly. They cannot fly fast.

---------------------------------

Click to enlarge; copyright Gert van Dijk

It is quite possible that some of the images are new to the readers. The one above, a phleph, has featured on the front page of the site at one time. Its formal name is Vanitas sursumvergenspropterpenuriaponderis, and yes, that does mean something...

From the IFB archives (2): the marshwalloidea

2011-12-10T16:44:00.009+01:00

The archives of the 'Institute of Furahan Biology' contain sketches of animals that later evolved into paintings (the sketches, not the animals) . This second foray into the deeper vaults of the archives reveals the development of the marshwallow, a large herbivore that like a hippopotamus spends much of its time in water. You can find the finished version on the land page of the Furaha site, and it is also visible in animated form on the 'walking with...' page.

Click to enlarge; copyright Gert van Dijk

I think this was the first sketch. I was experimenting with a new type of felt-tipped pin that was promised to behave as a brush. It did, largely, and that is why this sketch has such strong black strokes. The paper came for a stack used for polygraphic recordings, which is why it has yellow vertical lines on it. As you can see, the sketch shows an animal with a mane of hair standing in water. It has a somewhat bland expression on its face; perhaps it is wondering what it is doing there. The sketch does not show any underlying pencil lines but was done directly with the pen, which probably explains why the perspective isn't any good. Just look at the lower portion of its jaws: it is almost as if it is twisted to the right compared to the upper part of the head of the animal.

Click to enlarge; copyright Gert van Dijk

I did the same animal again later, this time with a pencil sketch overlaid with a version in blue ballpoint pen. The perspective works better here. The ballpoint pen version shows a smooth neck head shield protruding form the back of the animal's head. I must still have liked the brush-like pen, as I proceeded to go over it once more, this time with the thicker black strokes. The animal is still standing in water and still looks a bit daft, but seems to have a stronger personality than its predecessor. The complex shape of the head was the result of a conscious effort to avoid a typical mammalian head.

Click to enlarge; copyright Gert van Dijk

It may be difficult to see what is going on here. These are sketches in which I was searching for a pleasing composition. The theme is an animal standing in water, the surface of which is covered with lily-like leaves. The shadows show that the sun is behind the animal, so its shadow projects well before it. The sketch on the lower right is better in this respect, but looking back now I should have emphasized the diagonal nature of the composition.

Click to enlarge; copyright Gert van Dijk

This one shows the same idea, but the sun is now straight overhead. The lily-like thingies on the water surface are still there, but a new feature are the shadows of 'birds' flying overhead. Some of those are cast on the back of the animal itself. I wonder whether I would have succeeded with this approach: as the birds themselves would not be shown, would anyone be able to work out that those shadows were cast by four winged birds? 'Bird' is used here analogous to 'fish' in the Furahan context. For biological lay people, animal in water are 'fish', and for those people animals that fly are 'birds'. I know better, so do you, but that's how people are.
Obviously, I must have felt that the composition could be improved by just focusing on the head of the animal, as I not only went over the main lines there with a pen, but also divided that section of the sketch into 16 rectangles, a step that helps to redraw a composition in another format. That choice was chosen for the painting.

Click to enlarge; copyright Gert van Dijk

And here is the 'marshwallow' again in finished form. In this incarnation it looks irritated. I could easily have omitted all indications that we as humans read as emotional clues, and I probably should have. After all, it is not exactly likely that alien animals would convey emotions in a way that we can read. I probably liked it better this way...

Click to enlarge; copyright Gert van Dijk

Later, I thought about painting a herd of these marshwallows in the middle ground, being stared at by a predator in the foreground. For that I needed to think about a colour pattern. Here are two possible ones. The top one is very mammalian, but the second one is not. The shape of the limbs illustrates what happens if I do not pay a great deal of attention: they turn into mammalian legs. The hind ones especially go against the basic design of large hexapods, in whom the anatomy of the hind legs is -except for the feet- a mirror image of the front pair. In both, there are shoulder blades that are only loosely attached to the bulk of the body. The middle pair has a bone and joint connection to the corporal skeleton. For more on leg design, see previous entries in this blog: here and here.

Click to enlarge; copyright Gert van Dijk

Why have just one species of wallow? Indeed, shouldn't there be a group of related species, the 'walloidea'? I thought as much, and here are some. As you can see, there is a 'Protovolvulus species' at the right, in which males and females look the same. The one at the top is a male marshwallow, here called 'Disjecta membra', which means 'with strewn limbs'. The limbs that phrase refers to are not its own, but those of animals dumb enough to bother a marshwallow. In time, the name 'Disjecta membra' was replaced by 'Volvulus elongatus'. Some wallow species tend towards gigantism together with elaborations of the neck shields. Any resemblance with Ceratopsia is not coincidental at all. I have no idea why I came up with the name 'Disjecta pandorae', but to avoid any confusion I would like to stress that this sketch predates the film 'Avatar' by at least 25 years. 'Polyonyx vivax' seems to be the most elaborately coiffed wallow species. By the way, the gender symbols indicate that this how the genders look in the major portion of an animal's life. In most species, sex changes as a function of size and social importance, and 'indicator features' such as spikes on the neck shield change along with sex. It's complicated, I know...

Animals of the Future? Allons-y!

2011-11-29T20:06:00.004+01:00

This is a short follow-up to the last post, on the project of my French friends & colleagues: 'Demain, les animaux du futur'.

Messieurs Boulay and Steyer wrote that they were quite happy to see that the post had generated numerous pertinent responses, so there.

More to the point, they decided to provide a bit more information on their website in the form of two new videos, on on the 'Demain...' project and one on the terraforming of Mars. It seems that the firm of Cossima Productions is off to a good start. Here is a direct link to the page where you can see both videos. From there, you can also click on the 'YouTube' logos under each video.

Here is the one where Boulay & Steyer explain what the project is all about. Mind you, the quality of the video on this blog is less good than the version you can see on the Cossima site or on YouTube, so if you want a higher quality, use that route or just go here directly.

Yes, it is in French; do not act surprised, it's what people in France speak. Perhaps I can be persuaded to provide a translation, but right away I haven't got the time to do so.

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Additional text (December 2, 2011): With a bit of help by Marc in figuring out what they said I translated the text of the video. Any errors are my fault.

Sébastien Steyer:
"Marc and I both love science fiction. Every time we saw what films and other works in science fiction offered in the way of an exobiological bestiary, we had a thing or two to say about it. So, instead of criticising the work of others, we wished to create our own universe and to imagine speculative biology in Earth's future.
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For example, we designed a future flightless parrot, in which we envisaged a reduction of its wings up to the point where they disappeared altogether, with an accompanying lengthening and strong development of its legs. Bit by bit we came up with an animal we thought likely, ten million years from now.
---
This is no longer science fiction, it's more like 'fiction science'. It is a projection, but one taking known evolutionary, tectonic and climatological models into consideration."
---
Marc Boulay:
"Making a sculpture, regardless of whether of a past, a present or a future animal, involves an anormous amount of work in getting source material and discussions with scientists. That takes up about 90% of my time. The rest is applying that knowledge. Doing the sculpture takes up about 10% of my time. "

A future book on future evolution from France

2011-11-19T13:47:00.011+01:00

Click to enlarge; copyright M Boulay / JS Steyer

Yes, there will be a new book on speculative evolution, a real proper book, that you can actually hold in your hands. It will describe life on Earth 10 million years in the future, or well after man. Future evolution on Earth is a branch of speculative biology I have hardly discussed in this blog, but I thought I would make an exception for this project. Do not run to the bookstore just yet, as the book will probably be published in the second half of 2012. This means you have about a year to brush up on your French, because that is the language it will appear in.

It will be entitled 'Demain: les animaux du futur' ('Tomorrow: animals of the future'), and will be published by 'Éditions Belin'. The authors, Marc Boulay and Sébastien Steyer, told me that they are currently working on the second of what will be five chapters. Marc is a digital sculptor and Z-Brush expert, who has an extensive knowledge of animal sculpture and whose work has featured on this blog before. Does anyone remember me posting on an exposition in Brussels where future animals were shown, posted in February 2009? Well, Marc proved to have had a hand in their design, as I later found out and discussed here, here and here. Sébastien is a palaeontologist from Paris, who does not limit himself to going on fossil-hunting expeditions in Africa and writing scientific papers, but took the time to write a -very readable!- book on 'Earth before the dinosaurs'. If you like that subject, you might wish to take a look the French or Dutch versions; an English version is in the works. Together with Pierre Godlewski they have formed a firm, Cossima productions, to produce not just the book but other projects as well, probably including a television documentary as well as a book. The idea for the project began in 1999 and is completely independent of 'The Future is Wild'.

So what will be in the 'Demain' book? Obviously, we do not know yet, but you can get some glimpses at the site of Marc Boulay and of Cossima Productions. Perhaps the animals that were once shown on their sites will appear in the book. As these sites have been shut down, only some hints remain here and there, including on my own blog.

Click to enlarge; copyright M Boulay / JS Steyer

I really liked Benthogyrinus. The accompanying text says that it about the only surviving amphibian, a descendant of the frog species Xenopus. It has developed glands to expel salt and now lives in the seas. It reproduces in its larval stage and exhibits profound sexual dimorphism, i.e., males are much smaller and are shaped differently than females. For more images on this animal please read the original post.

Above is a demo reel of Diatrymimum boiseï, obtained from the links above. It is a large predatory bird, that has not just lost the power of flight but has lost its wings altogether, bones and all. It evolved from a parrot (Psittacus). As you can see the authors did their homework: whereas most people would limit their skeletal studies to some sketches, in this instance the skeleton has been worked out in full 3D detail. From then on the video shows how the body is shaped, and after that there are some colour studies. The background, with iits light to dark gray gradient, is typical for ZBrush. As a whole the demo shows what can be done with ZBrush (if you are a very accomplished 3D artist, that is!). What struck me is that the femur (the thighbone) is not horizontal as in ostriches but is oriented much more vertically, making the limb much more reminescent of that of a predatory dinosaur such as Tyrannosaurus. Such dinosaurs can afford to have their limb in this position because their tails balance the weight of the front part of the body, meaning that their centre of gravity is near the hip joints, and as long as the feet are directly underneath the centre of gravity, the animal won't keel over. Ostriches do not have heavy tails, meaning their centre of gravity is well in front of the hip joints. In order not to fall the feet still have to be underneath the centre of gravity, and the ostrich does that by having its thighs in a more horizontal position than Diatrymimus. I think Diatrymimus gets away with this by having a short and rather small body.

And this demo reel shows more of Marc's ZBrush work. There are ants, Burgess shale animals as well as dinosaurs and other Mesozoic animals, but about 40 seconds after the start there are glimpses of animals that may well be future animals, but whether they are part of the project described above, I do not know. Perhaps the authors will let us know. At any rate I will keep you informed when the book comes out, hopefully a year from now.

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Additional remarks (November 12 2011)

Marc sent me an email that he was happy with the post and added a file of a much better quality video. I agree that the videos I had shown you were not very good. The problem was not the source material, which was excellent, but in getting that quality here on the blog. The Google blogger program alters videos and shrinks them to fit one and the same size. Unfortunately, I cannot therefore replace the videos above with better ones. But what I can do, and should have done, is to point out where you can find better quality ones.

Both videos can be found on Youtube: here is the Diatrymimus one, and here is the 2010 demo reel.

Marc also added some other images for you to look at:

Click to enlarge; copyright M Boulay / JS Steyer

This is D. boiseï again, this time with lots of details of the head. I suppose that readers will have noted the development of teeth-like structures, lost by its bird ancestors a long time ago? The two commenters so far drew attention to the lack of feathers. I can understand how feathers might be lost on the head for predators: many vultures have unfeathered heads. But there is as yet no explanation for the total loss of feathers elsewhere on the body. We will either have to wait for the book, or perhaps Marc or Sébastien will take the bait and write a comment...

Click to enlarge; copyright M Boulay / JS Steyer

And a new species as well! It is called 'Spatamagnalis ruber'. If memory serves me right, a 'spata' is a short or broad sword, and ruber is definitely 'red'. Apparently, there are more flightless birds in this future. And featherless too... is it the climate?

From the IFB archives (1): the 'schaatsbeest'

2011-11-05T16:10:00.010+01:00

Every institute has archives. You cannot have a proper Institute with a capital 'I' without them. The 'Institute for the Advancement of Biological Studies on Furaha, Nu Phoenicis IV', also known as the 'Institute of Furahan Biology', or even shorter as the 'IFB', definitely has archives. You might think that the IFB, being a virtual Institute, would have virtual archives, but that is not the case.
I have a stack of old sketchbooks and loose sheets of paper containing sketches that I have amassed over the years. As archives go, this one is a right mess, as the papers are not in any order and the dates of the sketches and studies are not indicated. Some sketches contain the earliest appearances of animals that were later painted, others are just doodles, some contains ideas later incorporated into something else, and some show designs that never made it. I thought it might be interesting to show a few of those sketches, and will start with an example of the latter kind, one that nearly made it into a painting, but became destined for non-existence. So here is the world's first peek at the 'schaatsbeest'.

Click to enlarge; copyright Gert van Dijk

This is probably its very first appearance. I must have felt the composition was good from the start, as it hardly changed afterwards. In fact, I still like it. I wrote 'schaatsbeest' next to it, which is Dutch for 'skating beast'. For this post I decided to leave its name in Dutch rather than translate it into English. There are animals names in Swahili and French besides English on Furaha, so why not one or two in other languages? On the remote chance that you might wish to pronounce its name correctly, the 'ch' in the beginning is like the 'ch' in 'Bach' as Germans pronounce it, which is NOT 'bahk'. The 'aa' is like the 'a' in 'father' but longer, and the 'ee' in 'beest' is like the 'ay' in layer (if you think this is silly, remember that you English speakers are the ones who messed things up with your great vowel shift). Anyway, the schaatsbeest is ice sailing, also known as 'ice yachting'. If you do not know what ice yachting is, have a quick look at the Wikipedia entry, or here for photographs of present-day ice sailing.

Click to enlarge; source here

Just to be on the safe side, here is an example of a historical type of ship used in ice yachting. As you can see, the process is like sailing, but instead of a hull making its way through water there are skates allowing it to glide over frozen rivers, ponds or lakes.

Click to enlarge; copyright Gert van Dijk

And this may well have been the second sketch. Together with the first one it allows the beast's anatomy to be discerned: it has six legs, of which four are used to skate on, and the other two look like the front limbs of a mantis (this may very well be the first time that this particular configuration came up). There are four sails, derived from wings. The animal is sailing into the wind, which means that the wind is coming from in front and a bit to the side. This type of sailing requires the sails to be very taut, and results in large sideways forces on the ship, so ships sailing into the wind typically tilt over to the leeward side. The schaatsbeest undergoes the same forces, and in this case the two skating legs on the windward side are tilted right off the ice, where they help act as a counterweight.
The point of this second sketch was to work out the perspective. If you look carefully, you will see that the animal throws a shadow on the ice, indicated by vertical stripes, and below that you see its body mirrored in the ice (the perspective of a mirror image is easy, once you understand that you should act as if there is a second object behind the mirror). In this case, the mirror image allows the viewer to see the underside of the animal. I thought that this would make for an interesting composition.

Click to enlarge; copyright Gert van Dijk

This sheet of paper shows more takes on the same idea. I used to sketch multiple images right through one another at the time. I was playing with the sails and had a first look at colour. The colour sketch at the top shows a completely different kind of sail, reminiscent of a schooner rig. The bottom sketch shows two pairs of sails while the two other sketches show fused sails, with a mainsail at the back and a jib or genoa in front.

Click to enlarge; copyright Gert van Dijk

Here is a pencil sketch showing the schaatsbeest from in front. The odd object at the left is a squarish 3D arrow indicating the wind direction. The animal allows its body to be tilted, but uses its front limbs and the windward skates to balance it. Its head is held perfectly horizontally. The sails are also moved towards the vertical. I think that the thick lines where its back meets the mainsail masts were alterations to allow it do that with sufficient force. The small sketch towards the right show it sailing squarely before the wind, where it does not tilt and spreads out its four sails to make the most of the wind.

Click to enlarge; copyright Gert van Dijk

Finally, a very large pencil sketch. It looks like it is drawn on parchment, but that is only because I needed to manipulate the image for the pencil lines to show up at all. I had made a cardboard model, put it on a mirror, and based the sketch on that. That explains the thinness of the limbs and the lack of any perspective drawing guides.

I stopped development there. In hindsight, I may have been right to do so. While I still like the composition, almost enough to pick up the design again, an ecological point of view suggests this animal to be in trouble. It is obviously quite well adapted to move around on expanses of flat ice. Are these then around from most of the year? What does it find there to eat? The animal would probably be very clumsy on dry land, and its modified wings will not allow it to fly. Oh well; back into the archives, I guess.

Lifting the cloak on Cloakfish

2011-10-22T17:22:00.007+02:00

There is an odd difference between drawings and photographs of animals. In a photograph a galloping animal may be caught in time in just such a way that only one of its legs touches the ground. No-one will think twice about whether this is 'correct' or not. But do the same in a painting, and people will start thinking that the painter has it all wrong. Something like that happened to my Furahan Fish IV, shown in this blog earlier.

Click to enlarge; copyright Gert van Dijk

Here it is again. I received some questions where it right front fin had gone. Was it amputated or had I forgotten it? No, I replied, I worked out the perspective and the missing fin is simply hidden by the body. I admit that I saw these people's point and have been tempted to tweak the perspective a bit and have the tip of the 'missing' fin emerge from behind the body. Its absence seems to be disturbing in a way. While working on Fish and Cloakfish I experimented a bit with the reasons.

Click to enlarge; copyright Gert van Dijk

This image shows two versions of a ray-like species of Fishes IV. The top image shows a layer for the perspective lines as well as a layer containing some rough idea of light and colour. Layers, for those of you not familiar with computer painting programs, are the computer equivalent of a pane of glass on which you paint. The painting as a whole can consist of many such panes, each consisting a different bit of the painting. The trick is that you can make layers invisible, change their transparency or swap their order. I use Painter 11 as I like its tools, that resemble artists' brushes more than the tools of Photoshop CS5. As you can see from the sketch the perspective effect is fairly strong, meaning that parallel lines diverge quite a bit. Still, the drawing seems to work, perhaps because all parts of the animal are visible.

Click to enlarge; copyright Gert van Dijk

Here is an example of some Fishes IV as well as one species of Fishes V, the branch that gave rise to terrestrial hexapods -it's the only one with a neck-. The layout may seem odd, but what you are looking at is a putative two-page spread of a book. The six rectangles are meant to contain the text in three columns per page. If you think the green Fishes V species looks a bit like a plesiosaur you would be right, as there is definitely convergent evolution going on here. Then again, Fishes V have four jaws, four eyes, three pairs of gills, to name a few differences. This sketch is an experiment with a purely lateral depiction of animals, almost without any perspective at all. Some people use such approaches often, but I prefer full perspective views. But a few pages containing such almost schematic side or top views will not hurt, I think.

Apart from 'regular' Fishes, I have been working on Cloakfish, completely unrelated to Fishes I to VI. You will find cloakfish on the main Furaha page, but also here on the blog. Apart from a few sketches almost all my earlier work on cloakfishes involved computer graphics, because I wished to see their four 'cloaks' move while swimming. At present it is time to paint them, but I wished to get their cloaks right, and doing that by hand would be very difficult. So I took recourse to computer graphics, a process best described as 'practical' ('cheating' comes to mind, but why not use tools when available?). To help the process, I adapted earlier programmes in Matlab so I could produce a cloak with any shape I wished, as on the left, that is warped to produce waves progressing along it, as on the right. Right; make four of them, export them as 3D files, import them in a suitable 3D program (Vue Infinite in my case, and we are ready to play.

Click to enlarge; copyright Gert van Dijk

Here is an example. The left panel shows the four cloaks, striped to help visualise their 3D shape, attached to a central axis (that is called a 'dagger', by the way). The body proper is formed by some basic shapes such as cylinders and rectangles. I thought it might be worthwhile to put lots of parallel rods in the image that could help get a better feel for the perspective. I set the focal distance of the imaginary camera in Vue to 35 mm, and that is the image in the left-hand panel. The perspective looks believable, does it not?

The right-hand side was produced in Painter 11. I imported the image from Vue and painted a rough cloakfish on a semitransparent layer above it. I decided to play around with the front edge of the funnel. In that stage of their evolution, cloakfish were all filter feeders, so the opening in the front doubles as a food and a respiratory intake. Some cloakfish evolved feelers, and those are what you see here. I wasn't happy with the sketch though, and wondered whether the perspective was part of the problem.

Click to enlarge; copyright Gert van Dijk

So I went back to Vue, altered the characteristics of the 'camera' to give it a long lens, and repeated the process. Well, well. The result looked more suitable for an illustration that the earlier one, even though that one was realistic. More realistic, because the combination of the lens with the size of the animal resulted in a perspective closer to what you would see if you were a human on Furaha. Obviously, my attempt at 'mathematical correctness' did not work. Perhaps it can be as counterproductive as its political counterpart. Anyway, I was not happy with the funnel opening.

Perhaps it was time for a redesign. Should cloakfish really all be filter feeders? There certainly are small filter feeders on Earth (polyps etc.), but there is curious gap in size in filter feeders: either they are small or they are colossal, such as whales. I cannot think of sardine- or tuna-sized filter feeders. While I haven't thought that problem through, it seems a real one. I wanted cloakfish to occupy lots of niches and needed a good range of sizes. Perhaps the beasts needed a separation of alimentary and breathing tracts after all.

Click to enlarge; copyright Gert van Dijk

Here is an all-new cloakfish. The inner body protrudes forward from the funnel, that, as before, contains the gills. I played with it having four jaws, but decided against it. What you see here is the latest thing in cloakfish design: a regular mouth with a horizontal split. It need not stay that way, though. As you can see, their eyes have shifted forwards on the funnel to improve frontal vision while still having excellent all-round vision. And the perspective? Well, a view without strongly convergent lines, such as this one, may help viewers get a good feeling for the animal's shape.

From kudu to bogorbes

2011-10-08T17:22:00.007+02:00

There is too much going on at present for me to write any blog entries on arcane biomechanical biomechanics on other planets. For once, I will focus on some personal aspects behind a Furahan animal, an idea suggested by two anniversaries of past events. Twenty years ago I visited sub-Saharan Africa for the first time. I wished to see animals in the wild, reasoning that the slow degradation of the world's biodiversity would render such visits meaningless in time. I wasn't wrong about the degradation, but it is not too late for a visit yet.

I had a great time, camping in the wild, seeing animals as they are supposed to be, and revelling in an over-abundance of beauty. Any readers who have been to Eastern of Southern Africa may recognise African influences in my paintings.

Click to enlarge; copyright Gert van Dijk

Here is a sketch proving the point: a group of predators is enjoying their meal on a steppe or savannah, watching some large herbivores and being watched in turn. The scientist in me insists in adding that this is not a typically African scene: similar scenes have been played out on European, Asian, American and probably Australian steppes and savannahs countless times, with different species in the prey and predator roles for each time and place. But it is only in Africa that such biomes have not been wholly replaced by wheat fields, livestock pastures or the human habitat, explaining the strong association of such scenes with Africa. In my case, the associations have a strong personal flavour as well.

That visit changed my life because I met my wife to be during that trip. We got married a few years later, and visited Africa several times afterwards, something I stopped doing after she died, also quite some time ago. At the time she was as enamoured with the wildlife as I was. I returned home earlier than my travel companions, and immediately sent off countless rolls of film to be developed (it was 20 years ago). I sent a few prints to my fellow travellers, and decided to tweak one I would sent to my later wife in Paris, where she then lived.

Click to enlarge; copyright Gert van Dijk

I took out my oil paints and altered a photograph of a greater kudu, an antelope, standing on the shores of Lake Bogoria in Kenya. I added a third pair of legs in the front as well as a new neck and head, and masked out bits of leftover kudu. I varnished the photograph so my handiwork was not too apparent. I sent my 'cooked kudu' to her, and she had a good laugh with it. She mixed the photograph with photographs of her own of that trip. A friend of hers went through her stack of vacation photographs, said "Tiens, il y a six pattes" ("Hey, there's six legs") on encountering the photograph and then simply continued flicking through the pictures, without apparently realising that a large six-legged herbivore was more than just a trifle strange, in Africa or anywhere else...

My wife later dubbed the animal a 'bogorbes' (Venia lauta), and it has been part of the Furahan fauna ever since. You will find it on the cover of Sigismunda Felsacker's travelogue "Paleo Days" (see the New Hades book shop), and the blurb text there was written by my wife; not everyone in the Furaha universe is fictional.

"Maybe if you stick on another leg at the end of the tail?"

2011-10-01T13:05:00.008+02:00

Designing a novel way of walking for extraterrestrial animals is complicated. I tried my hand at designing gaits for large hexapodal creatures (see the main Furaha site), radial walking patterns and also explored walking with an odd number of limbs. In all such efforts the trick is to achieve something that looks interesting as well as believable. In the context of speculative biology 'believable' is balanced somewhere between 'Earth normal' and weirdness. One thing is clear though: you cannot get a believable result by assembling an animal of leftover bits and pieces, such as just sticking an extra leg on the end of a long tail.

Or can you? As usual, evolution on Earth manages to come up with designs that, if invented by a mere human, would fall in the category of unacceptable weirdness. The following video shows an insect that looks odd, but oddness by itself is fairly normal for insects. Look how it moves: most of the time insects walk with a double tripod gait: the front and hind legs on one side move in unison with the middle leg on the other side. When these three legs touch the ground they form a stable tripod. The other three legs meanwhile are lifted and swung forwards, and when they touch the ground, they will form a tripod as well. The two tripods are exactly out of phase, so when one hind leg is on the ground the other should be in the air. Now have a look at the hind legs of this interesting beastie, a trilobite beetle from Borneo. The original is here.

Its pairs of legs are in phase, a bit unexpected, but slow-moving insects can do that. But that is not all: it uses the tip of its abdomen as an additional unpaired leg. It curves its abdomen forwards, plants its 'leg' on the ground, and pushes backwards with it. Anatomically this may not be a proper leg, but functionally this animal certainly uses seven legs: it's a heptapod!

Here's another video. The beginning shows that this species can also walk with the front legs out of phase, but you do not get to see all legs that well. It is clear though that it uses the end of its abdomen as a seventh functional leg.

Why do these animals walk in this weird fashion? The gait does not look quick or agile. In fact, the animals appear to be rather slow and clumsy. A bit of research points to an answer. These 'trilobite beetles' are said to belong to the genus Duliticola, and using Google with that name results in a paper starting with the brilliantly surrealistic sentence 'There are two trilobite larva species in Singapore.' Apparently, the male and female of these species differ greatly in shape: the males look like typical beetles while the females are neotenous. Now neoteny is a condition in which sexual maturity occurs while the body is still in a larval stage. The axolotl is a famous example, and humans are sometimes thought to display neoteny as well.

But what does that mean for the strange gait of this apparently female insect? Well, it looks a bit like a regular adult insect, with a hard exoskeleton and all, but its general body shape is in fact that of a caterpillar. Caterpillars display complex gaits, not too surprising if you think about their body plan: six regular legs that will become the legs of the adult insect, a number of 'prolegs' (the knobby stumps further along a caterpillar's body), as well as final 'anal prolegs'. All of these are attached to a boneless body, providing endless opportunities of combining walking with stretching of the body. So that explains the trilobite beetle's walk: its' a caterpillar in disguise. Never underestimate insects' capability of oddness.

There is of course more to be told about caterpillar movement. In fact, at least in some species their gut moves inside their body before the outside follows up. The following video show that very nicely as well as the combination of body stretching with using legs. Perhaps there is a risk that you will learn more about caterpillar movement that you bargained for, but personally, I love details.

It's a bird, it's a plane, it's a... flying squid!?

2011-09-11T12:36:00.019+02:00

A year ago images of flying squid were in the news, including two short papers in Scientific American (here and here). Somehow I missed them at the time. Perhaps they are old news to readers of this blog, but I thought they were still very interesting. After all, cephalopods (octopus, squid and the like) attract attention from just about everyone with an interest in speculative evolution. I think Dougal Dixon was the first to have them venture out on land, a concept followed so often that it has become a cliché (but which does not mean that it was not a great idea at the time). I criticised the concept of 'walking with tentacles' in a series of blog entries later, reasoning that tentacles are so poorly designed to withstand compressive forces that evolution would turn them into limbs (here are the first, second, third and fourth posts on the subject). By the way, cephalopods with jointed legs would, for me, be much more interesting than ones painfully plodding about on tentacles. Unfortunately, their renal system is probably a much larger hindrance from them leaving the water than having tentacles; but I digress.

Cephalopods have jet propulsion, also a rather interesting feature to have aboard, and one that also crops up regularly in discussions on alien animal design. Some went so far as to equip animals with fuel-burning jets, something belonging in the needs-a-lot-of-faith category.

So now it turns out that some squids can leave the water, much as flying fish do, and probably for the same reason: to escape predators. And they use jet propulsion to do so. I wonder how people would react if squid did not exist and I would invent an animal with a double set of propulsion organs, fins as well as a jet: "What, two means of propulsion? That is improbable and inefficient!" Have that followed by the remark that they can also use their fins as wings and fold up their grasping organs to have a second pair of wings: "He's lost it this time!". Facts are often stranger than fiction, and flying squid are a prime example.

Internet searches revealed more pages and photographs of flying squid,including the following two ones. I checked two books on cephalopods I already had, and one book mentioned that the family Ommastrephidae is in fact known as 'flying squids'. The other book specifically mentioned that the fins are 'not especially well modified for gliding'. It seemed I had missed all of that.

This is a large image found here; The blogger program would not let me import all of it, so I had to cut off portions not showing squid. Even so, you may have to zoom in to see them properly. Some squid trail a stream of water behind them, that appears to be breaking up into drops in some cases. The text mentions that these images were taken as a series of rapidly taken images, and that this time series allows calculation of how fast the squid moved. That is obviously true, but unfortunately the results of those calculations were not stated, which is frustrating.

Click to enlarge; from: Bartol et al, Integr. Comp. Biol. (2008) 48 (6): 720-733

Squid squeeze a jet of water out of a tube, the 'siphon'. The image above nicely shows that the siphon can be turned around allowing the squid to move in either direction. The fins at the end of the body are a normal part of squid anatomy. Squid use both their fins and their jets to move around. The principle of jet propulsion has to do with actions and opposite reactions: pushing away a mass with a certain force results in you undergoing an equal force in the opposite reaction. The force gets bigger the more mass is pushed away and the faster it is propelled. In jet engines air streams in to the engine and out of it continuously, but in squid the propulsion is 'pulsatile'. The water is held in the mantle cavity, surrounded by muscles; when these contract water is forced out. Afterwards the muscles relax, the cavity expands and sucks in water for the next cycle. On the whole squid jet propulsion is nowhere near as efficient as swimming with a tail is, as fish do. Recent calculations suggest it is not as inefficient as formerly thought, but squid still do well do use their fins as well as their jet propulsion system. In fact, they may be better off for having two propulsion systems. I found some interesting material on that subject in a free scientific paper on the subject (from which I took the diagram above as well).

Click to enlarge

This image, found here, shows one flying squid in close up. The animal is flying towards the left. The image suggests that the fins are held in a V-shape, with the tips directed upwards. Holding wings like that is a design trick to prevent rolling about the body axis: when the animal rolls to one side, the wing on that side becomes more horizontal, so it will generates more lift. The other wing becomes more vertical and generates less left. The two effects counteracts the roll and help stabilise the body. At the other end of the animal the tentacles are held in a symmetrical way in a horizontal plane, and there appears to be a membrane between at least some tentacles. This position can only mean that the tentacles act as another wing. I cannot see on the large image whether the tentacle-wings are held in a V-position as well. The close-up seems to suggest they are not. So the 'flight plan' of the flying squid consist of two pairs of wings positioned far apart, with a long body between them. Now where have I seen that before?

Click to enlarge; copyright Gert van Dijk

Actually, only here, as far as I know. The Furahan Seasoar can be found on my website. I developed it consciously in an effort to see what could be done with a four-winged body plan. I reasoned that placing the wings far apart would place relatively much mass at the ends of the animal, making it more difficult to rotate to the left and right. The design would be stable, though, good for long and energy-efficient flights. In fact, I made a paper version once that flew quite well (which gives me an interesting idea for a future post...). The front pair of wings are held in a V-shape, but the hind pair are not. In truth, I did that only because it looked good, and I never stopped to think why one pair should be held in a V-shape and the other not. That arrangement looks a lot like that of the flying squid. Perhaps it does serve a purpose besides looking good.

The large image shows trails of water behind the squid. Does that mean that the squid are actually using jet propulsion to power their flight? Yes and no. Maybe. On the one hand it is certain that the jet allowed them to accelerate enough to leave the water, where resistance against movement is very large. That same force should have a stronger propulsive effect in air, which offers much less resistance to movement than water. On the other hand, weight is not a big problem in water, but it is in the air. Any water carried into the air to serve as 'ejection mass' for jet propulsion increases the mass of the animal and will therefore impair the squid's flying ability considerably. The good part of that is that the water is squeezed out, so the mass of the squid plus its store of water decreases quickly. As the store of water is depleted the squid gets an extra boost, which helps to propel it. There must be a complex optimum in there somewhere, in which the mass of stored water, the force of propulsion and the moment the squid leaves the water are all factors that, when balanced subtly, result in the best soaring ability. But such thoughts count in the long run of evolution. For an individual squid with a predator on its heels (so to speak), getting out of the water NOW regardless of any optimisation might be the wiser choice.

Between the Morae River and the Red Valley

2011-08-26T11:07:00.015+02:00

I discussed Brynn Metheny's 'Morae River' project once before in this blog. The project dealt with life forms in a certain geographical area called 'Solturna'. The animals there at first glance looked like Earth's mammals, reptiles, or fish, so you might think that the Morae valley might be somewhere on Earth. But a closer look revealed small but telling differences in anatomy, so you might think that the creatures perhaps stemmed from a not too alternate time-line and were mammaloid, reptiloid and ichthyoid. But a few animals departed so much from regular Earth stock to make you think that they required an extremely early divergence or an unearthly origin. Brynn gave no clue as how to place her creations, and preferred a fluid interpretation. Earlier this year she unfortunately decided to stop working on the Morae River. But that should those who never visited the site from doing so, as it is a great project even if it is no longer updated.

Luckily she did not stop producing odd animals. Far from it! I gather that she is making 'creature design' her career, which hopefully means that there is much more to come. There are several places where you can admire her work: she has a site on Deviant Art where she goes under the name of LenoreKitty. She has a site under her own name, brynnart.com, as well as one going by the name of Fishhook studio. I selected a few paintings for you to see here, and expect that they will make you hungry for more.

Click to enlarge; copyright Brynn Metheney

The pygmy esorifleu
As you can see, this is an arboreal creature with a strong bill, like a parrot's, and six limbs. The middle pair are placed at the top of the animal and are directed upwards, whereas the front and aft pairs are directed downward. There is also a tail, which looks like it is prehensile. This animal can only be a brachiating carnivore. It looks somewhat like my marblebill, to be found on the Furaha site but also in this blog (here and here). A fairly large design difference is that the esorifleu using its middle pair of limbs to swing from, whereas I chose the front pair. Brynn wrote me that the pygmy was designed for a creature design contest. I think the marblebill and the esorifleu are nice examples of convergent speculation.

Click to enlarge; copyright Brynn Metheney

Elegant hunters
And indeed they are. Mind you, the prey look rather dashing as well. The beaks of the hunters remind me of the mouth of a deinichthys. At first glance their body design seems to say 'bony fish from Earth', with its vertical tail, fin rays, gills and dorsal fin. But then you notice that instead of one pair of pectoral fins there are two, giving a jolt to the idea of what exactly they are. What I do not know is whether you have to know that two pairs of pectoral fins are impossible for that jolt to occur. Anyway, four gill slits is an unusual number as well.
I would like to see more of their prey, whose 'Bauplan' seems much more unearthly. I like the bumps on the front of the flippers. Not many swimming animals have those, but humpback whales have very knobbly leading edges on their enormous flippers, and in their case the turbulence they cause actually seems to help. Is that the end of a siphon I see on their sides? Are those expiratory outlets?

Click to enlarge; copyright Brynn Metheney

'Mamma'
No classification problems here: that's a perissodactyl unguloid, or a hoofed animal with an odd number of toes. But are those concentric structures external ears? Perhaps the animal is not Terran after all...
What I like a great deal about this one is how the animals are not simply shown in side view, but are much more three-dimensional. The calf's head cannot be seen, and the mother's head is turned away a bit as well. This is where the trained artist shows herself, I think.

Click to enlarge; copyright Brynn Metheney

A work in progress
Lacking a name, let's call it a 'wip'. If I see correctly there is just one pair of eyes, and the other markings on its head are nostrils and ears. Even so, this animal is more alien than the previous one, with the sail on its neck and particularly the spikes at the base of its tail. Now what are these doing there? They are not placed well for attack or defence, so perhaps they are for display purposes, and display to members of the same species always boils down to sex. Do the spikes serve to impress other wips, or do they provide tactile stimulation during procreation? I had better reign in my imagination here...
It's a beauty though.

Click to enlarge; copyright Brynn Metheney

Another work in progress
If it is, we might as well label it a 'wiptoo'. It is interesting how this head and neck study immediately evokes the notion that we are looking at a very large animal. One reason must be the relatively thick neck. Large animals need proportionately thicker limbs, and that goes for necks too (see here and here for the reasons). Apparently we are so used to seeing the results of these laws of nature that we immediately draw conclusions from seeing their results. Alternatively, of course, this could be a moderately sized animal from a heavy-gravity world, but I do not think so: its eyes are also small in relation to its body. They seem to be camera eys such as vertebrates have on Earth. While bigger animals generally have bigger eyes, eye size does not increase directly with body size, so large animals have relatively small eyes. As with neck thickness, the observer takes these cues and judges the size of the animal, consciously or unconsciously.
Its skin glistens. You can tell from the linear nature of the reflections that its skin is smooth, and I wonder whether it is wet because it just emerged from a swamp or something similar or because the skin itself is wet or oily. A large animal with a permanently wet skin would need a permanently moist and saturated environment. Perhaps it lives as brontosaurs were once thought to do: in humid steaming swamps.

Click to enlarge; copyright Brynn Metheney

There are no animals on this painting, but the image contains a promise. The website of the Red Valley project is already up, but there's not much to see yet. We are promised that animals will appear there in the Fall, so hopefully Brynn won't keep us waiting too long. She wrote me that she is not going to reveal all about the planet: "I might know details about the whole of the planet and such but as far as my viewers are concerned, I'd like it to just be about this valley." I agree with that sentiment: always leave the viewer or the audience hungry for a bit more, and a hint that there is in fact more does wonders to whet the appetite. She added: "I want the flora and fauna to feel alien enough but I want viewers to relate to them as well."
From what Brynn has done in the past, I think she will succeed. The text on the Red River site also states: "No regions, no classification, just this place as it is." Oh very well, I get the message: I should stop trying to classify these animals to see where they belong and what makes them work.

Hmmm; as if I could...

It's a Fish! (yes, again...; this one's in 3D, though)

2011-08-20T14:59:00.010+02:00

Click to enlarge; copyright Gert van Dijk

This is just an extra post. Regular readers may remember that I tried my hand at ZBrush in the past. I still try it from time to time, but found that it, as everything, takes time to master, and digital painting takes precedence. The ZBrush people keep out churning new options, so I will probably never get around to mastering even the simpler elements. Pixologic, the same firm that produces ZBrush, now offers a similar program but completely free: Sculptris. It offers only a few controls, which really helps to learn it. It is very impressive. The controls are the same as those of ZBrush, so experience with one program helps the other. I could not resist trying it, and found it a pleasure to work with. Go to the Pixologic site to see what can be done with it, because my meagre efforts only show what you can do with it in one evening. It is very useful for 2D artists who do not plan to go into 3D, becaue it is easy to sculpt a rough shape to help get the perspective right.

Click to enlarge; copyright Gert van Dijk

So here is a Fish, of the Fishes IV type; I showed one before. I painted four now for The Book, and will not publish these paintings here on the blog. But having done that, Fish IV anatomy came natural to me, and here it is: six flippers, usually attached higher on the body as you go aft, a large head merged without a neck to a stiff body, and three gills on each side with separate inlets but a fused outlet. You knew about the four eyes and the four jaws. As I said, typical Fish IV anatomy.

Click to enlarge; copyright Gert van Dijk

---------------------------------------------

P.S. As Luke remarked in the comments section the Fish shown so far are fairly large. Aren't there smaller ones? Yes, there are. I had realised I had a tendency towards larger ones, so I explored the possibilities of size on purpose.

Click to enlarge; copyright Gert van Dijk

Here is a rough sketch in Painter11. Its smaller size is indicated by relatively large eyes and by having thinner flippers, that as a result resemble fins more (the second pair are probably too large). I also experimented with a general 'fishy' look by giving it a glistening skin. The counter-colour pattern (dark on top, pale below) is probably a universal trick to blend into the background.

Create your own planet (using Celestia)

2011-08-13T11:44:00.020+02:00

The theme of this first tutorial is how to produce image of a fictional planet of your own making. Personally I use two programs to do so: Celestia and Vue. Celestia was used to produce, among others, the 'satellite images' on my site. It allows you to explore the universe, and provides detailed images of just about any object in our solar system, shown with appropriate orbits, orbital speeds, etc. The program is driven by scripts that are completely open, meaning that anyone who wants to can change almost anything. The result of this is a lively community in which you will find all kinds of real rockets and artificial satellites, but also space ships and entire solar systems from science fiction. There is a 'motherlode' and a forum.

This tutorial aims at absolute beginners as far as Celestia is concerned, but you will need some experience with a suitable graphics program. At the very least you need to be able to paint, select areas and cut and paste them. Photoshop is an obvious candidate; I have used Paint Shop Pro in the past, and now also use Painter11. I am told GIMP is also good (and free...).

The planet Mars will be given a new surface, which, in the computer world, is a 'texture'. In its simplest form that is just a colour image, but additional tricks include producing a 'bump map', allowing mountains or canyons to stick out or to be recessed, creating a more powerful 3D illusion. Another trick is adding a 'specular reflection map'. With it, areas such as seas and lakes will gleam when light falls on them, in contrast to duller areas such as land. Finally, planets can be draped in 'cloud maps', making them look like Earth.

Click to enlarge; copyright Gert van Dijk

How do you design an interesting planet surface? Or, how do you draw the surface of a 3D sphere on a flat surface? By distorting it. Severely. The image above shows a sphere with a texture of the planet Furaha, along with a cylinder on which its surface is projected. Cutting the cylinder open produces the flat map in the back. Most distortion will occur around the poles, which is very visible in the image above. The arrows all point to the same part of the same continent. On the cylinder and the flat map that area looks much broader than it is on the sphere. The simplest way not get frustrated by polar distortion is to leave the poles featureless, achieved by filling it with sea.

The map above is twice as wide as it high; those are also the proportions used by Celestia, and they make good sense. The height of the map is the distance from the South to the North Pole across the surface, or half the circumference of the planet. Walking along the equator provides the entire circumference, ending up as the width of the map. This is about the simplest map projection there is, known as a 'Plate Carrée' projection. You should use sizes that are multiples of two, because Celestia wants you to. A good size for a blank map is an image of 1024x512 pixels. If ever you are ready for more, use 2048x1024 or multiples of that.

Click to enlarge; copyright Gert van Dijk

Here is a silly map of 1024x512 pixels with a few continents on it, labeled A to E. Note that B, C and D have the same shape. Let's cover Mars with it; you can download it from the above image, or make your own version (in which case it should be 1024x512 pixels!).

Celestia should be on your computer. If not, download it and use it until you can at the very least find the planet Mars and get it into view.
Close Celestia if it is open. Find the Celestia folder on your computer. Open it and locate the 'textures' folder. Within that is a 'medres' folder. It is filled with many planetary surfaces that you can study at will. Find the file 'mars.jpg' and have a look. It should be 1024x512 pixels. Save it, also in the 'medres' folder, but now as 'OLDmars.jpg' (in case you later want to replace your own planet with good old Mars).
Now is the time to take either the silly image I provided or your own 1024x512 image. Save it in the Celestia medres folder under the name 'mars.jpg'. Don't use another size, don't use another name.
Run Celestia and go to Mars. And there you are. Marvel and gloat.

Click to enlarge; copyright Gert van Dijk

You may note that there are some ridges and craters on your planet: those are the result of the bump map for Mars that is still in place. When you are ready marvelling it is time to stop gloating: the two sides do not match up. Continent A straddled the western edge of the map, and E the eastern one. Well, a map has edges, but a sphere hasn't. That simple fact tells you at the edges of the map are trouble areas. Remember that the flat map is a cylinder cut open, so the surface should be contiguous along the vertical seam. One way to do that is to use a featureless sea along the seam. But there is a better way. This boils down to cutting up the map in two halves: a western and an eastern one. Switch their positions, and the former edges now lie against one another at the centre of the image. Edit them to produce a nice continuous shape. How you cut the map into two halves depends on your graphics program. In Photoshop you can do the following (correct for CS5): Select Filter, then Other, then Offset; once there, check the box for 'wrap around' and fill in half the width of the image (which is 512) and press OK. That should do it.

Click to enlarge; copyright Gert van Dijk

Above are the results of first rearranging the squares and then editing the map. I chose to let the continents A and E fuse to form 'EA'. After you have worked on the centre of the map you can decide to revert the procedure and change the squares around again, also shown above. You can also decide not to bother, as both are equally correct.

There is a good chance that you will have noted that the continents B, C and D differed in shape on the globe, whereas they are the same on the map. The nearer the poles you get, the more pronounced the distortion is. It is extremely difficult to predict how a 2D shape will look like in 3D. The usual result is that shapes near poles tend to look pinched, i.e. many features will look like lines pointing to the pole, which is ugly and unrealistic. There are three solutions: as you may guess, the first is to fill the area with sea. The second is to muddle through: look at your latest version in Celestia and work on the flat map to correct pinching. Then save the latest effort as mars.jpg again, close Celestia, open it again as it otherwise does not refresh the map, and repeat. The third solution is the most elegant one, and requires that your graphics program can do a conversion from polar to rectangular coordinates as well as vice versa. Photoshop can do so (I learned this one from a tutorial on the Celestia forum). In Photoshop this transformation makes the rest of the map fuzzy, so it is best to use it with only part of your map:

- Select the top area of your map as above: the entire width, and roughly one quarter of the height.

- Copy this as a new image and jot down its size (for instance 1024x142, or 1024x199, etc). It should look like the one above.

- Transform this into a square of 1024x1024 pixels ('Image', then 'Image size', uncheck 'constrain proportions', change the vertical pixel size to 1024, OK).

- Go to: Filter; Effects; Distort; Polar; select 'rectangular to polar' and press 'OK'. This results in a new square image as if you are looking down at the pole. That is the top one of the two above. Edit it at will, resulting in something like the one above.
- When ready, all the steps should be reversed. First revert the polar distortion: go to Filter; Effects; Distort; Polar; select 'polar to rectangular' and press 'OK'
- Give the square its original rectangular size again, which you had jotted down (use the same route: image; image size, etc.)
- Select the entire rectangle and copy it to memory
- Go back to your world map and paste the edited polar area in your map in the right area at the top.
- If need be, merge layers so you can save it again as 'mars.jpg'

Click to enlarge; copyright Gert van Dijk

The map looks rather different now, and in Celestia there is no more polar pinching! For the south pole you can rotate the world map by 180 degrees so the south comes out on top.

If you can handle seams as well as prevent 'polar pinching', you are well on your way. I may need to do another tutorial on how to design suitable colour textures, bump maps and specular reflection maps. Do not forget that there is quite a bit of material on the Celestia Motherlode, on textures as well as on many other things.

Click to enlarge; copyright Gert van Dijk

Here is a picture made with Vue of the same globe. I added a bit of 'bump mapping' and some reflectivity. There is a free version of Vue 9 that hasn't got all all options, but you can definitely make images such as this one with it. Those who wish to experiment will find it here.

Click to enlarge; copyright Gert van Dijk

I prefer Celestia for images with a realistic astronomical view. For other illustrations Vue is nice; here is a model of Furaha with a colour map, bump mapping, with a grossly exaggerated height, and different reflectivity of sea and land areas.

Ballonts under pressure (Ballonts IV)

2011-07-30T13:47:00.005+02:00

The previous post dealt with the physics of balloons, with an eye on what it would take to design a viable animal using a lighter than air approach. The main thing that emerged, not very surprisingly, was what makes a balloon work is the difference in density between the gas inside it and the air outside it. It was also clear that balloons below a certain size do not even get off the ground; bigger is better for balloons. And that could raise difficulties, for how do big ballonts breed if not by producing little ones?

Click to enlarge; copyright Gert van Dijk

Seeing how small ballonts cause trouble, here's one painting in the Furaha collection with small ballonts. It was destined for oblivion regardless of whether the ballonts it showed could work. It was an early painting; the hexapod (Caeruleacornu rubrum) is much too insectile and I don't like the colours or the composition anymore. The 'balloon tree' (Mollum trisiphonitum) is a mixomorph making use of sunlight to create little hot spots in which interesting thermal reactions take place. That gave me a nice excuse to paint half-transparent bubbles, always a nice thing to do. Molla (that would be the plural of 'mollum') launch their young into the air in the form of a larvae suspended from a balloon sac. The adult mollum blows gases into the sac, forcing it upwards through one of its siphons. Once the sac pops free, a valve between the sac and the larva closes, and the larva drifts off into the wild blue yonder (or hither, as the case may be). The larva is supposed to crawl around a bit before becoming sessile for the rest of its life.

As you can see, the mollum contains some of the ideas mentioned in the comments on the previous post, such as using a ballont for just one stage on a being's life cycle, or having it produced by an adult. What it also shows is the kind of ballonts I would have liked to have, i.e. fairly small ones... Oh well; what remains to do now is to play around with all the factors in the ballont equation to see how we can get as big as body mass as possible with as little a sac as possible.

A thinner membrane
In the calculations the membrane consisted of a Mylar-like substance. The Mylar party balloons you see everywhere use metal to resist gases diffusing through the Mylar. Whether animals can do that as well is uncertain, but, as fishes face a similar problem with swim bladders, and their sealing method works. I looked at spider silk to see if that would be better, but its density is about the same as that of Mylar. I did not dare to make the membrane thinner than 0.1 mm, which I thought was stretching it already (sorry about that one...).

Change the gas in the balloon
The lighter a gas is inside a balloon, the better, and hydrogen is as light as it gets. About the only way to get less mass would be to heat the hydrogen: after all, hot air balloons float because one cubic meter of hot air weighs less that one cubic meter of colder air. Does heating hydrogen make a difference? The 'ideal gas law' nicely describes the relation between pressure, volume and temperature of a gas. After expanding the ballont model a little bit the model allowed a calculation how much mass of hydrogen could be saved to fill a balloon with a 1 meter radius for a range of temperatures. This is what came out: this hypothetical balloon could lift 4.8519 kg with the inside and outside both at 15 degrees centigrade. With hydrogen heated to 25 degrees less hydrogen was needed to get the same pressure and so the balloon could lift more: an additional 12.4 grams, to be precise.

What!? A bit more reflection clarified why this was so. A hot gas requires fewer molecules to exert the same pressure as a colder gas, and the differences in the amount of molecules needed determines the difference in mass, i.e. how much it lifts. But hydrogen weighs so little that the reduction doesn't amount to anything. It does if you are dealing with a heavier gas such as air. In air, there's not much point in using a hot hydrogen balloon. By the way, those designing their own ballonts should make certain that the bladder is filled with hydrogen only. Water vapour is much heavier than hydrogen, so the bladder should not be 'contaminated' with it!

Change the composition of the atmosphere
Adding heavy gases to your atmosphere will increase how much mass a ballont can lift. Earth air largely contains nitrogen and oxygen, but there are heavier gases. The real heavyweights are noble gases such as krypton (3.7 kg per cubic meter) and xenon (5.86 kg per cubic meter). Radon is even heavier but radioactive. You can dream about replacing half of the nitrogen in the Earths air by xenon: the density of the air would increase 2.4 times, and so would the lifting power of a hydrogen-filled ballont. The snag is of course that heavy elements are very rare in the universe, so such an atmosphere would make little sense. Some other gases might help, such as chlorine, sulfur dioxide or benzene. Large amounts of those would create a nice atmosphere for ballonts. Do not ask me to design a biochemistry to make such an atmosphere probable; I would not know.

Change atmospheric pressure
Another way is to increase atmospheric pressure. Gases can be squeezed, and the physics aren't complicated. Say a given volume of air on a planet X would have a mass of 1 kg; the same volume of hydrogen might have a mass of 0.1 kg. That leaves 0.9 kg to lift something with. Now we increase the pressure twofold. The same volume of air now masses 2 x 1 = 2 kg, and that volume of hydrogen masses 2 x 0.1 = 0.2 kg. The difference now is 1.8 kg, also doubled. So atmospheric density has a linear effect on liftable mass.

Click to enlarge; copyright Gert van Dijk

The graph above shows liftable mass; see the previous post for how that was arrived at. Start at the line for 1 atmosphere (that is Earth itself). If you increase the radius of your balloon, the liftable mass rises, and more so for as the radius increases. We knew that. Go to the next line, one for two atmospheres of pressure, and you get a similar curve. It is just higher.

Click to enlarge; copyright Gert van Dijk

The image above does something similar. It builds on the balloons in the previous post. Under '1 atm.' (that would be Earth) there are two balloons, one with a 0.5 meter radius and one with a 1 meter radius. Underneath are slung the bodies they can just lift. Now let's see what happens if we decide that we want balloons to lift these same bodies, but under a higher atmospheric pressure. The balloons get smaller, but not as much as you might think or wish. For instance, the balloon that had a one meter radius under one atmosphere of pressure can have a radius of 79 cm under two atmospheres of pressure (that radius defines a sphere with half the volume of the with a one meter radius - with twice the density, the mass is the same; see?).

No matter what you do, that third power effect of radius conspires against having small ballonts. I think that I will delve into the possibilities of atmospheres with hundreds of times the pressure of Earth in a later post. That should do justice to 'Jovian floaters'; in the New Hades bookshop you will find that they were supposed to be so common in every gas giant as to be boring. We'll see.

You can of course keep on increasing atmospheric pressures even on a terrestrial planet, but there will be consequences; there always are. Think of wind forces, think of hothouse effects; there are probably lots of other effects. One is 'drag', or the force that resists moving through fluids or gases. If you want a ballont to move against the wind, you will want as small a bladder as possible to reduce drag. With an enormous bladder all a ballont can do is float with the wind, against which resistance would be futile. In a dense atmosphere the bladder would be smaller, making a self-propelled ballont more feasible. But drag also increases with density; as I said, there are always complications, even in a simple Newtonian universe.

In the past I had worked on the physics of ballonts a bit but not in detail. Those earlier efforts had made me settle on a pressure of about two earth atmospheres for Furaha. Two atmospheres is about what you get with a depth of 10 meters of water on Earth. Human bodies can adapt to that, as evidenced by underwater habitats. I did not dare, then or now, to go higher for fear of the consequences. What the current more detailed analysis yields is that smaller ballonts are, how to put it, exempt from existence.

But large ballonts will stay, at least for now. How Furahan ballonts breed and what their evolutionary history is are things that need quite a bit of reflection. I would not be surprised if regular commenters solve these issues long before I ever get round to them...

Ballooning animals and Newtonian fitness (Ballonts III)

2011-07-15T09:30:00.021+02:00

Click to enlarge; copyright Gert van Dijk

I have always had a weakness for balloon animals. Not the toy balloons that squeak when you twist them into shape, but lighter-than-air living beings. I would like to see such 'ballonts' float silently and majestically over the plains. One such is shown above (well, two of them). Nice, isn't it? I could do screensavers if anyone wants them.

Click to enlarge; copyright Gert van Dijk

Smaller ballonts, less than a meter, are even more to my taste. These might descend from a rain forest canopy to siphon fluids from carcasses, or something equally mysterious. No wind there, so it might be a good environment for them. They could flap around a bit as well.

Click to enlarge; copyright Gert van Dijk

Less dramatic but much more common would be tiny ballooning seeds drifting with the wind across the world, forming a sort of aerial plankton. Books on biomechanics never mention lighter-than-air flight, but do not discuss radial flight either, as neither exists on Earth. The usual question is whether the absence of lighter-than-air animals on Earth signifies that evolution so far forgot to take off in this direction or that the idea won't fly.

I have written about ballonts before (mostly here and here), but this time the focus will lie on 'hard science', so there will be some formulae and a few calculations. Sorry about that, but it is not really difficult. The goal is to see what is needed to achieve a ballont that can lift a nice hefty body with as small a gas bladder as possible. Because there is a bit of explaining to do we will not get further than Earth in this post.

The first step is to realise that floating in air works exactly the same as floating in water. As 'buoyancy' you will find that in biomechanics textbooks (for instance here and here). It all starts with Archimedes' principle, who stated that 'the upwards force of an object in water equals the weight of the displaced volume of water'. That works in air too, but let's start with water, because that is a bit more intuitive.

Archimedes started with 'the displaced volume of water'. OK; let's make a box of 20 by 20 by 20 cm and hold it under water. It is not difficult to find the volume of the water it displaces: that is the volume of the box itself, which is 0.2 x 0.2 x 0.2 = 0.008 cubic meters.
To get weight we first need to know what the mass of that amount of water is. The density of fresh water is 1000 kg per cubic meter (sea water is a bit denser). For 0.008 cubic meter, we get a mass of 0.008x1000= 8 kg.
Weight is a force, not a mass. It is the product of mass with the gravity constant g, and on earth that is 9.8 m/(s^2). So the upwards force acting on our box is 9.8x8= 78.4 Newton.

Upward force = g x Density of water x Volume of object

Nice, but so what? Well, the presence of g in the formula means that the upward force increases directly with gravity. On a world with twice the gravity of Earth the upwards force will be twice as large as on Earth. One consequence of this is that a floating object rises faster than on Earth. But will it also lift a larger body mass, which is what we want? As we will see, the answer is no, but first we have to calculate how much mass a balloon can lift. The first step to get there is to calculate the object's own weight. We know how to calculate weight: upwards force was weight of water, after all:

object weight = g x Density of object x Volume of object

The net force is obtained by subtracting them, which can be written as follows:

net force= g x (Density of water - Density of object) x Volume of object

The gravity constant g is still in there, but focus on the rest of the formula. If the object is denser than water the net force is downwards -it sinks- and if the object is less dense, it will float. No matter what you do to g, that balance will not change. Interesting; the amount of mass that can be lifted does not depend on gravity. Without g, the formula describes a mass (density times volume). For a net upwards force, that resulting mass is what the object can lift:

liftable mass= (Density of water - Density of object) x Volume of object

Here is an example: Suppose the object is made of cork with a density of 250 kg/cubic meter. Fill in the numbers for cork and fresh water and you get (1000-250) x 0.0008 = 6 kg. If you tie a mass of 6 kg from the cork cube, the ensemble would just stay in place under water, as its combined density now is the same as that of water. (1) All we need to do to turn this into a formula for the bladder of a ballont in air is to supplant 'water' with 'air', and 'object' with 'bladder':

liftable mass= (Density of air - Density of bladder) x Volume of bladder

The density of air on earth at sea level is only about 1.2 kg per cubic meter, so we need very light materials to make a ballont work. The choices are limited. Helium would be great, but it is probably difficult to find on a terrestrial planet, and concocting a biochemistry to produce helium may be taking things too far. Hydrogen is easy to find, can be fabricated, and only weighs 0.09 kg per cubic meter. We are now almost ready for the real stuff.

Click to enlarge; copyright Gert van Dijk

The image above shows a simple ballont scheme. It builds on the scheme above. Here are the ingredients, supposed to work at one Earth atmosphere and 20 degrees centigrade:

A spherical bladder. It consists of a membrane, which will weigh something. I have great faith in the ability of Darwinian evolution to come up with amazing substances, so I chose something like Mylar. The membrane will be just 0.1 mm thick, and its density is 1.2 times that of water, based on PET and similar substances. The radius of the sphere allows its area to be calculated, and with that its mass. That is a downwards force.
The bladder contains hydrogen gas. Its radius gives us its volume, and together with the density of hydrogen (0.084 kg/(m^3) at about 20 degrees) we get the mass of the hydrogen. This is another downwards force.
The volume of the displaced air is found from the radius of the bladder and the density of air (1.2 kg/(m^3)). This is an upwards effect.

Subtract the two downwards effects from the one upwards one. What we have left is how much mass the bladder can lift. We will tie a body underneath with a density of 1.1 times that of water. (2)

Click to enlarge; Copyright Gert van Dijk

Click to enlarge; copyright Gert van Dijk

The graph above shows results for bladders of 0.1 to 1 meter radius. The blur line (displaced air) is what determines the upwards force, and the membrane (black) and the hydrogen (green) pull downward. The red line is the difference, and that determines the mass of a body you can suspend from the bladder. Hm; a balloon with a radius of one meter still only lifts about 3 kg, as shown in the image below the graph (the man is a 3D object I found on the internet). While 3 kg is enough to build an interesting animal -think of a cat!- the relative sizes of the bladder and the body mass are not pleasing. Even if we clap on some wings to the body, the animal will still be extremely vulnerable to the slightest wind. It does not even get close to the kind of animal we want. I think we need to do better. Even a protoballont should have some advantage of its bladder, or else Darwinian evolution will not take off.

Click to enlarge; copyright Gert van Dijk

Perhaps the ballont seedlings work better, so let's do the job for a radius of up to 40 cm. Hang on: the red line goes below zero, so the smaller ones cannot lift anything at all! The reason is that their membrane is too heavy at small sizes. On further reflection that is understandable: the mass of the membrane increases with the square of the radius, and lifting ability (volume) with the third power. For very small ballonts, the membrane can outweigh the lifting power! Alas, there go the balloon seedlings. Struck down, not by a lack of Darwinian fitness, but because they are unfit in a Newtonian universe.

Click to enlarge; copyright Gert van Dijk

Let's try again for balloons with a radius of 1 to 5 meter. That's better: we can lift hundreds of kg now, enough for an impressive animal, with limbs, a digestive system, a hydrogen-producing organ (however that works), tentacles for tethering and grasping food, etc.. You may protest that the membrane is too flimsy for an animal of this size. I agree, but even with a thicker membrane, compartments etc., the effect of the third power of volume will easily priduce a net lifting force. Unfortunately, a balloon with a 5 meter radius is still very large indeed, nowhere near the shape we were looking for....

So it is the density difference of the lifting gas compared to the surrounding air that makes a balloon work. Perhaps surprisingly, gravity does not determine the liftable mass, or, at any rate, not directly. Some elements scale with the square of the radius and others with the third power. We saw earlier that this limits the size of land animals (start here for that subject). For ballonts it is just the opposite: bigger is better, at least as far as liftable mass is concerned. Whether the animal is viable in the Darwinian sense is something else entirely. Earth is a poor place for ballonts: blame Newton. To get them to work we need to manipulate not the ballont, but the planet! More on that in the future.

(1) In reality, the object you tie underneath the object also has both weight and an upwards force. The figure of 6 kg holds for the mass difference between the two.
(2) The body also displaces a bit of air, but that has so little mass we will ignore its upwards force.

Purple Plasmid's Fentil

2011-07-02T20:51:00.013+02:00

As confusing titles go, this one must achieve a fairly high score. What it means is that there a fictional moon Fentil, designed by someone named Purple Plasmid, who in real life goes under the name of Dan Emmerson. You will find his personal page on Deviant Art here, and his page on the planet Fentil right here.

If you, like me, are on the lookout for interesting projects on speculative biology, Deviant Art is not a bad place to search: it has enormous numbers of images and they are usually labelled sufficiently clearly to find what you are looking for. Some images of exobiological animals are very good, but quite often there is just one, and I much prefer a collection, a background story, or, in other words, more than just one image. Fentil has both background information and a collection of images, and so fits the bill nicely. There are over 60 images: some maps, some sketches, and some more elaborate designs. Dan's work exudes enthusiasm. Let's have a look.

Click to enlarge; copyright Dan Emmerson

These are 'pump fish', whose bodies are essentially cylindrical. They propel themselves by pumping water through heart-like chambers arranged one after the other, as the image shows. I like that design; that in itself is not surprising, as it is very much like some of my own designs that swim using peristaltic pumps (look for them on the water page, under 'swimming with tubes', or directly here if you do not mind losing the menu structure). I never named my own beasties, something I should rectify. One day I might actually just do that... Anyway, like my own creatures, pump fish probably do not show much movement on the outside when they are moving around. I started to wonder how many of these pumps should be placed one after another. For my 'peristaltic tube swimmers' I reasoned that one cycle moving along the length of the tube would be enough. In the pump fish case, you can see that the last segment is narrower than the front ones. If the same volume leaves the animal at the back as goes into the front in the same time, but through a smaller opening, the velocity of water must be higher, providing more propulsion. Do the successive chambers work at higher pressures, and is that the reason there are several?

Click to enlarge; copyright Dan Emmerson

I like the design of this 'sea sparrow': an elegant shape that seems very workable. They remind me of some sea slugs on Earth. The slug I had in mind is right here, and if you like sea slugs do not forget to have a look at the rest of the site they appear on. An intriguing part of the sea sparrow's anatomy is the combination of several paired fins with a large unpaired one at the back, giving it very original appearance. I would very much like to see an animation of how it moves.

Click to enlarge; copyright Dan Emmerson

A 'spot of fishing'. More precisely, it is a 'Rorschach sea sparrow' catching a pump fish. The accompanying text states that sea sparrows can fly and also chase their prey underwater. Gannets combine swimming and flying on Earth, although they are much better at flying in air than at swimming underwater. I suppose that it is possible to shift the point where an animal is at its best.
Dan's style with its flat colours and clear lines reminds me of some 'bandes dessinées' that use the 'ligne claire', such as shown here. I like this particular style. While seemingly simple, appearances are deceptive here. Dan wrote me he uses Flash for his artwork.

Click to enlarge; copyright Dan Emmerson

What you see here are some Fentil 'cloverheads' in the act of laying eggs. Cloverheads are herbivores that travel in great herds across vast plains. There are various cloverheads to be found on the Fentil section of Deviant Art. They all remind me a bit of Barlowe's animals, particularly as regards their feet, thatall look like elephant or sauropod feet. I think that this type of feet is very out of place in a fast-moving animal, but the explanation for that will have to wait for a post on what toes are good for.
What you might not appreciate is that you are looking at a first: this image had only been published before as a work in progress, but now it is final. A scoop for 'Furahan Biology and Allied Matters'!

Click to enlarge; copyright Dan Emmerson

These are 'Bghelly baskets'. These animals use sunlight to help raise temperatures in their gut sacs, which is a nice idea. They are larval forms using echo-location. Again I find the clean design very appealing.

Click to enlarge; copyright Dan Emmerson

Bone trees: without doubt they are among the most alien of Purple Plasmid's inventions. I would love to see a landscape painting with lots of them. The text provides a factual and neutral description about how they grow they way they do, but not why they do so.
Most plants on Earth have an enormous surface area in relation to their volumes, what with all the flat leaves and slender branches and twigs. Cactuses are notable exceptions: with their rotund shapes and no leaves to speak of, they clearly went for a very low surface-to-volume ratio. It is not difficult to work out why a cactus has a shape different from almost all other plants: a small area restricts evaporation, and their environment is very light anyway. As a bonus the large volume allows reserve water to be stored. Bone trees may look like cactuses, but they are found in regions where fresh water is plentiful, so there must be something else going on.
I thought that it might have to do with their skeletons being brittle, but Dan assured me that that was not the case. Instead, Fentil orbits a planet and suffers from frequent eclipses and the attending drop of temperature. This is what he wrote: "During this time, most plants hide within a protective shell, or retract their leaves (bone trees pull their leaves back into their shells) or just re-absorb the valuable photosynthetic tissue, which is usually free-floating in a transparent gel."

Click to enlarge; copyright Dan Emmerson

As hinted in the image above, There may very well be a website about Fentil in the future -another scoop!-, allowing visitors to click on cladistic trees to see what kind of animals they are dealing with. That sounds like a excellent idea. I hope Dan gets around to building one.

Furaha in the Science Section of NRC Handelsblad

2011-06-19T13:56:00.012+02:00

Well, when I came back from travelling abroad I found that 'NRC Handelsblad' had indeed devoted ample room to the Furaha project. 'NRC', as it is known, is a Dutch quality national newspaper. The weekend edition has a 12 page science supplement, and this weekend's supplement had three pages on Furaha: the cover and the spread in the middle.

I am afraid I cannot direct you to the relevant pages on the internet to have a look for yourselves, as these are open only to paying customers. Those with subscriptions can download a good quality pdf file. I have a subscription and have the download, but will not publish it here. After all, the newspaper is supposed to make money. Then again, at some point in the future I may yet do so after conferring with the newspaper people. For similar reasons the images below will give you an idea what the article looks like but not in enough detail to read it. Most of you would be unable to read it anyway, it being in Dutch, my native language. It is a very nice article, written by Lucas Brouwers, who also writes a blog -in English- on evolutionary biology.

Here is the cover. I took it from the digital edition, meaning the contrast is much better than in the printed edition, and the colours are also closer to those of the original. 'Wetenschap' means 'science'. (The two words may not overlap entirely. The English version of Wikipedia has a nice entry of the meaning of the word science: "Over the course of the 19th century, the word "science" became increasingly associated with the disciplined study of the natural world including physics, chemistry, geology and biology. This sometimes left the study of human thought and society in a linguistic limbo". In Dutch 'wetenschap' seems to used in the latter broad sense more often than in the narrow one).

Click to enlarge; copyright NRC / Gert van Dijk

Anyway, this is the 'woolly-haired shuffler', that can also be found on the Furaha site; it also featured in the Furaha blog when I first posted it on the main site. The name is a correct translation from the Dutch 'wolharige schoffelaar'. In both languages the adjective 'woolly-haired' was of course taken from the name of the 'woolly-haired mammoth', a name I have always considered as odd as it is funny. I do not think there are other animals, extant or extinct, whose name expresses a quality of their pelt. I have never heard of the 'silken-haired panther' or the 'greasy-pelted otter'; perhaps in poor prose, but not in an animal's name. The text of the paper uses 'wolharige schoffelaar' as intended, but the headline, after translation, reads 'Hairy shufflers and radial flyers'. Newspaper headlines are often written by other people than those who write the body of a text, for reasons unknown to me. Perhaps there was not enough room for the full name, but now the name states that the animal is particularly hairy and it is not...

Click to enlarge; copyright NRC / Gert van Dijk

And this is the inner spread. Regular readers will recognise most images. Two have not been published on the site though, eroding my store of fresh images a bit more. Mind you, the text does not go into what they are or why they look the way they do, so some mystery remains.

You might wonder why a science section of a serious newspaper devoted three pages to a speculative biology project, and that was what I asked the journalist before the interview. He answered that neither he nor his colleagues had any trouble with a mixture of solid science with creative and less factual matters. I am glad of that. Science is too often treated by scientists and others as if it is so serious that you should speak only about it with a straight face and in hushed tones. Well, without creativity science would not only simply not work but would be nothing more than drudgery. I hold similar views about the speculative side of matters, where I prefer to see a mixture as well: fantasy is not the same as idiocy. The best of science fiction is characterised by a 'sense of wonder' as well as a 'what if?' attitude. You cannot do science without them.

Furaha in 'NRC Handelsblad'!

2011-06-15T21:32:00.002+02:00

That won't mean anything to most readers...

But I am talking about a leading high-quality Dutch newspaper, and if everything goes well they will devote quite a bit of attention to the Furaha project in next Saturday's edition.

Kortom: Nederlanders of Vlamingen met belangstelling voor Furaha: let op de wetenschapsbijlage van NRC Handelsblad van zaterdag a.s.!

Its a bird, it's a plane, it's... a tetropter (tetropters IV)

2011-06-04T17:32:00.010+02:00

The nice thing about computer animation is that it allows you to actually see thing that you could only dimly imagine beforehand. One image that has been sitting in my mind for many years is the following: you see a dusty plain, and a herd of handlebars (Latifrons imperator) come galloping in from the right hand side of the image in the distance, and then wheel towards the viewer as if they were performing a well-rehearsed cavalry manoeuvre. I can almost hear them too...

Unfortunately I do not see anyone spending a small fortune to make this a reality, so I will have to content myself with what I can do myself, with my PC, at home. Some visions therefore remain locked in my head, but a few more modest ones do find their way out. Making tetropter flight visible is something I thought I worked on for quite some time; today I can show you a near-final result. Near final, because nothing creative is ever truly finished. In this case, the camera should move, the animals should vibrate in rhythm with the wing beats, there should be more details, there should be motion blur, and there absolutely has to be blurring to mimic a limited depth of field and through that create the illusion of small size.

Still, what I can show you is the principle of the thing. It's not a movie, but an illustration of wing movement in slow motion. Tetropters have been described several times on my blog. A summary of the tasks involved in animating them is found here, and entries on their design and wing movement patterns are here, here and here. In short, they are radial flying animals, whose four wings can do a 'double clap and fling', invented by yours truly, and later also by other people in the flying robot business. By the way, the movement of tetropter wings is not all that different from the complex way in which Earth insects move their wings.

This is an animated scheme to show how it all works: the wings are planes that are warped as they cycle through their movement cycle, so their shape is different depending on were they are. Where they are is governed by rotations along the x-, y- and z-axes, and all these paths can be altered and edited. The Matlab programs that do all this in the end write lots of 'obj' files: those are files describing 3D shapes; one is produced for each wing for each frame of the cycle (there are usually 120 frames in a cycle). A script written in Python then loads in a scene containing a body shape without wings in Vue Infinite, adds the appropriate wings per frame and stores the images. These are then used to form an animation, and those are what you see here.
The 3D shapes of the wings consist of 1600 small triangles, which is more than enough to show supple movement. As they are they do not look like wings at all, but there is another trick to take care of that.

The trick in question is to add transparency and colour. The transparency mainly makes unintersting parts invisible, but it is also useful to make the wing itself partly transparent as here. To create the fly-like animal above (Bombilator musca) I used an image of a real insect wing found on the internet, and used that to create a transparency mask. All of a sudden, the boring rectangular 'wings' produced by the Matlab program take on a biological appearance. Please do not look too closely at the body of the animal: it is a simple shape cobbled together in Vue. As you can see the animal has four legs and two sets of eyes: upper ones, presumably to scan for danger, and lower ones, near the food gathering end at the bottom.

A bit of colour makes a lot of difference, so here is a farfalloid, resembling a butterfly in overall appearance (Farfallapter caeruleus). Indeed, I stole its wings from a real Earth butterfly, albeit with some warping and editing. Mind you, quite a bit is lost in the conversion process.

Click to enlarge; copyright Gert van Dijk

To show that, here is a still of the Farfallapter; better, isn't it? Then again, you can see how crudely the wing is linked with the body...

I guess I now no longer have any excuse to put off work on the 'Flying with...' page. It is probably also time to redesign the site. I have already looked at that, but the days where you could learn HTML in two evenings seem to have gone for good.

How many legs are best for megamonsters?

2011-05-22T15:02:00.010+02:00

About a year ago I wrote two posts about what happens to legs when an animal is scaled up (here and here). In a nutshell, if you make an animal's body twice as big, the new body will weigh eight times as much as the old one and not twice as much. If you make the legs twice as big, they will not be strong enough to carry the new weight, so the only solution is to make the legs more than twice as thick. The result of all this is that legs have to make up a larger proportion of a very large animal than of a small one. There is a limit to how big you can make an animal: at some point the legs need more food than the body can deliver, or something equally silly.

Click to enlarge; copyright Gert van Dijk

Last week Jan asked a question on the bulletin board of the Furaha site asking which body plan would be best for really big animals. That question made me think: the more legs there are, the smaller each leg can be to carry the body. What does that do to the mass of all legs together? If the total mass of six slender legs would be less than that of two thick legs while doing the same job, than having six legs would be a better design for very large animals than having two. That would be a nice outlandish and unearthly solution! It is shown above in a rather silly image (the human figure came with the program and is there for scale only).

Whether it would work or not was not intuitive to me, so I did some homework and came up with the work of Robert McNeill Alexander (if you are interested in biomechanics you will encounter his work many times). In this case, part of the answer was described in this book Optima for Animals.

Click to enlarge; copyright Gert van Dijk

The reasoning starts with tubes. There are excellent reasons why vertebrate leg bones and insect legs are tubes, and why tubes are such important structural elements in technology. They are about as strong as solid rods of the same diameter, but weigh a lot less, and doing the same job with less bone is a good idea. The three tubes above all have the same outer diameter, but the hole down their lengths differs in diameter. In papers on the subject you will find an very important parameter 'k': it describes the width of the inner hole as a fraction of he outer diameter. In the left one k is 1, so the hole is tiny. In the middle bone k is 0.5, and in the right one k is 0.9, meaning there is just a thin shell of bone. A value of 0 means no hole at all, and a value of 1 would mean the bone is infinitesimally thin (in simple words: there is no bone!).
Are all these bones equally strong? No, they are not. If you just take bending forces, there is a nice formula which contains three items of interest: the 'bending moment' M (the force that the bone needs to withstand), our friend 'k', and the radius r of the outer side of the bone (there is only one thing else and that is a constant K for the material - ignore it-).

Here it is: r=[M/K(1-k^4)]^0.33

If you keep the force M constant you can calculate what the radius is for any given value of k. Let's do so.

Click to enlarge; copyright Gert van Dijk

The image above shows what happens for four values of k: 0, 0.3, 0.6 and 0.9. As you can see, the value of the radius increases as well: the thinner bones have to be wider to withstand the same pressure. Note that that is hardly the case when the holes are fairly small. In fact, the effect is only really noticeable when k increased form 0.6 to 0.9. Does it matter? yes: the cubes in front of the bones represent the mass of the bone itself, and that nicely shows why tubes are good. They are all equally strong, but the thin-walled ones weigh a lot less.
On Earth, things are more complicated for mammals because the holes in the bones contain marrow. Marrow, while less heavy than bone itself, still makes the bone as a whole heavier. A bone with a very thin shell will be wide and will contain lots of marrow, defeating the purpose to make bones light. For mammals with marrow in their bones there is an optimal value for k, at which the bone as a whole weighs the least; that value turns about to be about 0.63. If, however, you manage to put air in the hole instead of marrow like birds, than the story becomes different and you can increase k. Above around 0.9 the bones the become too susceptible to buckling, so there is another optimum value for air-filled bones: a value of 0.9 is excellent. Our hypothetical megamonster shall therefore have air-filled tubular bones with a value of k of 0.9!

We still are not there yet. The real question was what happens if we give the animal more legs. Let's assume that the forces are simply divided among the legs, so with four legs each leg has to carry exactly one fourth of the burden. Remember that there were three parameters of interest in the formula: The bending moment M, the outer bone radius r and k. Set k to 0.9, and then we can calculate r for four bending values. The values per leg are 1 (the animal has one leg), 0.5 (two legs), 0.25 (four legs) and 0.125 (eight legs).

Click to enlarge; copyright Gert van Dijk

This picture show the resulting bones, along with the number of bones. As you can see, the bone for an animal with eight legs is a lot less thick than for the one with just one leg. So far so good. The smaller bone must weigh a lot less than the bone for the one-legged animal, which is what we wanted. Then again, there are now eight such bones, so the question is what their combined weight is.
Each bone of the two-legged megamonster weighs 63% of the one-legged one, so the two bones together weigh 126% of the one bone. That is not what we wanted, as the two legs weigh more than the one leg. Does it get better if we add more legs? Well, for four legs each one weighs about 40% of the one bone, and together they weigh 159%. For eight legs, each one weighs 25% of the one bone, so the total weighs 200% of the one bone.

How disappointing... I had hoped it would be the other way around. Now it seems that fewer legs is the better way to save weight if you need a mega-monster. Obviously, giving it just one leg is not practical; there would be a big risk of falling, and the only way to move would be to jump in a series of bone-shattering hops. Two legs is quite feasible; just think of carnivorous dinosaurs. Four is also good. In a last-ditch attempt to save the concept of multi-legged megamonsters I could say that having six or eight legs provides safety as a possible advantage. A two-legged monster with a broken leg is doomed with certainty, and a four-legged one probably is. But a six-legged one could deal with one broken leg and hobble away.
You might expect animals with a multi-legged body plan to lose some limbs as they grow bigger and bigger as a measure to save weight. Such limbs might be given another purpose than locomotion, so they could develop into, well, just about anything. They could develop clavigerism or centaurisation, also interesting.

I'm still disappointed though...

Wildlife in the Star Wars universe

2011-05-07T09:35:00.013+02:00

The Star Wars films are great adventure movies, but you wouldn't think that there was much biology going on, would you? The Star Wars universe is obviously swarming with intelligent creatures from many different worlds, and these worlds must equally obviously be filled with animals, but you do not get to see many of those. it's not what the films are about.

In the second film there was the 'tauntaun' on the ice planet Hoth, and as a hairy mammal-like animal with the body plan of a bipedal carnivorous dinosaur that was an intriguing invention. Otherwise, not many in the early stages came across as great exobiological inventions. In fact, quite a few some could not be taken seriously at all: just think of the gigantic snake-like animal living in an asteroid (in a vacuum!), large enough to have the Millennium Falcon fly between its teeth. Or take the 'Sarlacc', a carnivorous monster buried in the sand on Tatooine: all you see of it is a gigantic mouth in a pit in the sand, reminiscent of an antlion but scaled up to a gigantic level. Its very existence implies that there are lots of rather stupid animals ready to stumble into it maws. No-one would take such a creature seriously from a biological point of view, and no-one should; it's not what the films are about.

Still, there is a book about the animals in the Star wars universe, showing someone cared. It is called 'The Wildlife of Star Wars. A Field Guide', by Terryl Whitlatch and Bob Carrau. Terryl Whitlatch has been working as a 'creature designer' for several of the Star Wars films. Typing her name into Google results in so many hits that I do not need to provide many links. Still, here is one with a video interview, and here are two on character design (one and two).
The 'Wildlife' book first came out in 2001. I had somehow missed it completely until recently, when a reprint was issued. I found another book of hers showcasing other work, not related to Star Wars: 'Animals Real and Imagined'.

The Star Wars book seems to have many creatures in it that did not appear in the films as far as I know. I have to be careful here, as the three newest films (I, II and III) did not make much of an impact on me, aimed as they seemed to be at children. I suspect that most of the animals in the book were not in the films at all, which would imply that Ms Whitlatch had more or less free reign in designing them.

The sillier animals such as Giant Space Slugs of over 900 meters long, and the above-mentioned sarlacc occur in the book, should you wish to know more about them. The animals that I assume to be Ms Whitlatch's inventions were much more to my liking. In a way they conform to the general exobiological theme of Star Wars. In it, intelligent beings are almost always humanoid, with two legs, two arms and a sort of alien-looking head that is rather larger than the standard Earth issue human head. The films started when digital creature design did not exist, and alien design followed time-honoured principles, involving actors in rubber suits. Hence the big heads.

Ms Whitlatch's aliens more or less follow such principles. The book deals with life on several planets, but you will not be able to determine their planet of origin by looking at their body plan: an animal could come from one planet as well as from the next. Whereas nearly all intelligent beings are humanoid, animals also share many design principles with Earth animals. Quite a few are 'mammaloid', meaning they look a lot like mammals with odd heads. There are also plenty of aviforms and reptiloids, as well as combinations of designs. It is interesting to compare this design strategy with that of Mr Broadmore's Victorian Venusian life forms discussed recently: these were specifically designed to evoke a sense of displacement, i.e. of 'alienness'. Instead, Ms Whitlatch's life forms might be just around the corner. That makes them more believable, but inevitably less alien.

Regardless of the degree of their 'alienosity', the animals are all superbly well drawn, with an intimate knowledge of animal anatomy and behaviour. The 'Animals Real and imagined' book contains drawings of existing animals in addition to fantasy ones, proving once more that Ms Whitlatch is a very skilled artist. I will go through a few of her drawings, scanned from the two books. As I did not wish to damage the books, I had to crop some drawings a bit, for which I apologise (you could all get the books yourselves...).

Click to enlarge; copyright Lucasfilm Ltd.

These are Motts from the planet Naboo, revealing how mammalian their body plan is. The way the legs fold, the number of joints, the general shape of the head, all these things say 'earth mammal'; 'ungulate' in fact. But look at the ease with which their poses are captured, and the green thingy walking away from the motts is much more 'alien'!

Click to enlarge; copyright Lucasfilm Ltd.

Also from Naboo, these gullipuds are, as the text says, amphibians. They resemble puffer fish or indeed, some Earth amphibian in being able to inflate their bodies. I like the sense of humour in this and other drawings.

Click to enlarge; copyright Lucasfilm Ltd.

The tree-dwelling Shaupaut. This is another mammaloid. Its elongated fingers are apparently used to 'fish' for avians flying by.

Click to enlarge; copyright Lucasfilm Ltd.

These animals are apparently extinct. They are labelled as stalking birds from Alderaan, and are obviously modelled on large African ground living birds, called 'ground hornbills'. These walk in rows over open fields, hoping to disturb smaller animals so they can be caught and eaten. These birds are doing the exact same thing.

Click to enlarge; copyright Lucasfilm Ltd.

These flying animals are urusais, and while they are members of the same species, there is an enormous difference in anatomy: the male is the one sitting upright balanced on its tail. It has four wings, while the female admiring him only has two. Now that is a rather fundamental difference. I doubt that any animals on Earth take 'sexual dimorphism' to such extremes. You would think that such large differences in shape would result in the two sexes being subjected to very different evolutionary pressures, with resulting different sets of genes for male and female bodies. Earth's insects may be thought to have two sets of bodies as well, but there the two act in different stages of life. It is an interesting concept to have something like that defining the two sexes. I have my doubts however that the differences can go so far as a having different numbers of wings.
The text says that their span is about two meters, which means that they must be very heavy. Their bodies and thick tails look good, but do not appear to be designed to save weight. Light bones? A heavy atmosphere?

Click to enlarge; copyright Design Studio Press

This one is not from the Star Wars book, but from the other one. It represents one of the few designs that I do not really like. The reason is that it reminds me too much of the six-legged forms in Avatar that I discussed earlier. Like the Avatar animals, this one does have six limbs, but not as three pairs with their own characteristics, but as one pair of hind legs and two pairs of identical front legs. In fact, their muscle anatomy shows the same problem as Avatar's thanator: the front limbs are, like those of Earth mammals, connected to the axial skeleton almost entirely by muscles. Note that the two sets of muscles seem to run through one another...

Click to enlarge; copyright Lucasfilm Ltd.

I would rather end with something I like better: the Nuna from Naboo, which is a very interesting and humorous drawing. The one on the left is a male, inflating his wattles and hissing to underline his dominance. You can see how well Ms Whitlatch combines animal anatomy with the expression of emotions. The emotions are very readable to us, which is probably not at all would you would expect from alien life forms. Then again, emotions help tell a story, and that is done very well here.

Three years on

2011-04-24T11:20:00.006+02:00

More than once in the three years I have been writing this blog I thought there were no more interesting speculative biology projects to be found on the internet, but each time I was wrong. Will the supply dry up? Perhaps not: there are more and more exquisitely detailed Z-Brush monsters, but mostly those are orcs, dragons and the like. In other words: they are not very interesting from a biological point of view. The reverse situation can also be found: well-thought out projects with artwork that does not do it justice. I guess I will simply have to wait and see how much content I can find to fill the 'allied matters' component of the blog. The number of page views slowly went up over time, which is rewarding.

So how about the 'Furahan biology' component? There is progress, if you account for the glacier-like advance of a very large project that you do not really have time for. Then again, in the last three years I got to grips with InDesign, Photoshop, Painter and XBrush (not that I am proficient in any). The most noteworthy skill I am trying to acquire is digital painting, which is the most needed one. I think I need to do some 10 additional illustrations of the "It's a fish" type, and then I will have some 15 two-page spreads to show to potential publishers. An example of those can be found in the New Hades book shop on the Furaha site: got to the brand new 'Living World Series' and you will find the 'Encyclopaedia of Furahan Wildlife' (also shown here). I aim to use that lay-out to present the book to publishers.

Rough tetropter animation; copyright Gert van Dijk

It is not difficult to think up many new animals or plants; many forms that I have now could do with some adaptive radiation. But my interest is mostly aroused by more complex puzzles. As an example I will explain the struggle to produce a good tetropter flight animation. The basic principles have been outlined before (start here to work back in time), but for good measure I have repeated an old animation above. As you can see the animal is shown from below, and the four wings move to and fro while rotating. They also move through one another, because the animation uses stiff planes for the wings: it is not good enough. I want a better one firstly, because I am curious: I wish to see what a spotted farfalloid looks like, when its beating wing reveal electric blue surfaces at one point in their cling and flap cycle, and bright orange ones the next! The second reason is that I would like to paint a variety of tetropters -talk about infinite variety-, and getting the perspective right of four warped surfaces in complex motion can be done by hand, but would be easier to manipulate by computer. I will break the problem into pieces:

Problem 1: defining movement
The wings can easily be modelled as surfaces in Matlab. These move through the wing cycle, meaning there are different requisitions for movement around the x- y and z-axes. To control them I wrote editing programs, now nearly done. The surfaces cannot remain simple planes throughout the movement cycle, but will have to be bent and warped. The animation above shows where I am now, meaning at the phase where all the 'warp factors' have to be tweaked to get it right. What you see here represents 'untweaked warping' though!

Problem 2: exporting the wings
The 3D program I am most familiar with is Vue Infinite. I had already written a program to convert Matlab patches to obj. files, which helps. But I then stumbled upon a new program, ad that was the imported wings for successive frames did not end up at the same spot in the scene. Apparently Vue calculates the mean of all x-, y- and z-coordinates to calculate the centre of an object, and if the object changes shape so does it centre. Well, I can counter that by shifting the object each frame to compensate. This needs work...

Click to enlarge; copyright Gert van Dijk

Problem 3: texturing the wings
Obviously, the wings will need interesting patterns on them as well as partial transparency. That, as well as bump maps, proved to be in the obj. definition and could be manipulated.
Here is a rough example of a warped wing with transparency and all in Vue.

So now you may understand why it has taken such a long time to put up a 'Flying with...' page, along the 'Walking with..' and 'Swimming with...' pages: the tetropter flight animation has to be ready first, and that is a big job.

"A Venusian Bestiary", in Which Greg Broadmore Illustrates Monsters Before They Are Gracefully Slaughtered

2011-04-09T15:00:00.017+02:00

"By golly, that's a splendid specimen! Blast its head off so we can turn its legs into umbrella stands, what?!"

This is not a literal quote from Lord Coxswain, but it might perhaps be one, suggesting a somewhat utilitarian and egocentric attitude. Lord Coxswain is a character from the 'Dr Grordbort' universe, in which Victorian style people (well, men, really) travel to Venus and have a jolly good time, helped by rayguns designed by 'socially inept boffins'.

Here is a short video to set the atmosphere: "Venus is doomed part II" (also found on YouTube or on the Dr. Grordbort page. As you can see, Lord Coxswain's attitude is that the last surviving animals of a species had best be bagged quickly, lest some other fellow acquire it for a foreign museum, and that wouldn't do, would it? Hence, Coxswain and his fellows -good chums all- take a healthy pleasure in shooting anything alive, animals, natives, whatever.

The person behind this yarn-ripping steampunkish universe is Greg Broadmore: a painter, creature and prop designer working for Weta in New Zealand. If neither 'Weta' nor 'Greg Broadmore' rings a bell, let me remind you of the dinosaurs and other creatures in King Kong, District 9 and other Weta work. Absolutely brilliant illustrations. In fact, Mr. Broadmore's work has featured twice before on this blog: once as a riddle animal (also here) and once when the King Kong book was discussed. He now develops the 'Dr Grordbort' universe, which has already yielded two books, rayguns you can buy (really!) as well as some stuffed Venusian insect-analogues that you can hang on your wall (really! Here's one and another).

I think his creatures are fascinatingly creative; he does dinosaurs, insectoids and various other stuff, and all of it so lively and so extremely well painted. There is also quite a lot of his material to be found on the internet. The 'Dr Grordbort' pages show that particular universe, and besides that he has his own website with a few galleries of work. If that is not enough he was interviewed at some length (part one and part two) on a website on creature design that most of you will probably like a lot even without Mr Broadmore's work on it.

In fact, those links should be enough to make this post worthwhile, but let me add a fairly large series of paintings on Venusian wildlife (these are not all). In time-honoured fashion I shall present my ramblings on what I think of their anatomy. The images were all taken from the sites mentioned above and are presented at a nicely large size, so be certain to enjoy them as best you can.

Click to enlarge: copyright Stardog

The shallow-beaked grogan's four columnar legs suggesting a large size (Venus' gravity is about that of earth, so relationships between body mass and leg diameter should resemble those on Earth, assuming bones of equal strength. I like the neck design: like limbs, necks could consist of a few large segments instead of a larger series of small ones. The 'biramous' (split) design of the front legs is also interesting, and is a basic characteristic of Earth arthropod limbs. Having part of the limbs fused must call for some dextrous motor programming, as I wrote earlier.

Click to enlarge: copyright Stardog

I cannot immediately think of a purpose for the sail on the back of this thingy, and in such cases sex is always something to keep in mind; perhaps the sail is a prop to impress its mates. The arms functioning as jaws are rather nice. Again, such designs work well in Earth's arthropods, and there is no reason to assume they would not work on bigger animals. But are there no eyes? Or are the spots arranged in a row along the head all eyes?

Click to enlarge: copyright Stardog

A large knuckle-walker with switch-blades for toes; is it a predator or are those for defence? It does not look particularly fast, so to be a a predator its prey should be very slow. The other Venusian beasties look quite athletic, so I would guess it's a herbiore or omnivore. There are more 'headarms' here, and I think there are eyes. lots of them.

Click to enlarge: copyright Stardog

Now this one needs some explaining. Its body is slung low, and the legs zigzag a lot and are splayed, meaning that this stance calls for lots of energy. It could be a jumper, but it looks very large for an ambush predator. The whole front looks like a giant mouth, with the four black prongs resembling canines. This time I really see nothing looking like eyes. Not having eyes is probably a very unlikely event in animal evolution. Eyes seem to evolve so easily and must convey such advantages that it is hard to think of a reason to stop them evolving. All you need to start is some light sensitive tissue, some movement ability and the most basic of nervous systems, and you are off (unless there is total darkness).

Click to enlarge: copyright Stardog

Ooh, another jumper: Unwin's double-backed shrovel. The viewpoint does not suggest great size, and the Grodbort pages show it to reach knee height. It is wonderfully alien.

Click to enlarge: copyright Stardog

This one reminds me a bit of an okapi: that must be the sloping back and the colour pattern. I wonder why there is a segment of both the hind and front legs that cannot do much mechanical work as depicted, because these segment more or less double up against the next segment. Then again, perhaps that is the point: these segment don't do anything in their current stance and are not supposed to. Once unfolded, they might be used to advantage, and this is just their 'fold after use' aspect. Well, if it isn't true, please admit that it is a nice idea.
Again, no eyes, I think. Barlowe tried animals without eyes (Darwin IV in Expedition), and I thought that that was a mistake, particularly if you do have bioluminescence.

Click to enlarge: copyright Stardog

Ha, some action! Coxswain in motion against the dimple backed vroxel! As I said, the feet, once divulged of bones and cleaned of flesh, do make excellent umbrella stands gracing any home.

Click to enlarge: copyright Greg Broadmore

More action! But just wait a minute... That's not a Furahan rusp, is it? (rusps are on the land page or directly here). It might be; it could be! What! We cannot have people like Coxswain murdering Furahan animals left and right!? That's no way to behave! Is he mad? The murderous swine! Stay off my planet!

Swimming in Sand III: real and robotic sandswimmers

2011-03-26T14:20:00.012+01:00

The previous two blog entries on sandswimming animals (here and here) made it clear that those who wish to populate their fictional worlds with animals swimming in sand will either have to restrain their fantasy or choose to forgo realism. Sand is not a forgiving medium; a 400 m sandworm, as in Dune, must shift millions of tons of sand to move, which is simply too unlikely to consider. While that reasoning argued against giant sandswimmers, the fact that any sandswimmer must lift all the sand above its body restricted the choices even more: sandswimmer cannot dive deeply. Facts can and often do spoil beautiful fantasies; sorry, but that can't be helped. This leaves sandswimmers as fairly small animals that swim just beneath the surface. Not surprisingly, this describes real sandswimmers quite succinctly. There appear to be several: there are various lizards and at least one mammal, the African golden mole rat.

http://www.nordicphotos.com/en/details/1350398

Here is an image of such a mole rat: Eremitalpa granti. There do not appear to be many studies focusing on how mole rates 'sandswim', but what there is reveals some interesting facts. Apparently someone has already measured how much energy it costs: sandswimming costs 80 times as much energy as running on the surface! That is a heavy price to pay, but sandswimming is still much less costly in energy terms than burrowing, i.e. scraping at the soil and carrying it away to create a tunnel that will last for a while. Of course, you can use a tunnel many times, meaning its cost decreases as you use it more often, in contrast to sandswimming: each trip is as expensive as the next. Unfortunately I could not find any video material of a mole rat sandswimming, so I cannot show you that (the main -but not only!- reason being that such a video might show some sand moving, but not the mole rat underneath...). But if you wish to know more about them, there is at least one nice entry on them in Darren Naish' justly famous Tetrapod Zoology blog.

I did find something else that is interesting for those who wish to design sandswimming animals: how do they breathe? There are two problems here; if breathing involves expanding the chest against the outside world, the sandswimmer is in trouble, as that would require some additional shifting of sand. So you had better design an air pump that only shifts volumes within the body, keeping the external volume unchanged. The second problem is whether the poor sandswimmer can extract enough oxygen from the air between the grains of sand; if it then breathes out, does the air circulate fast enough to get fresh air with the next breath? Perhaps it should suck in air at one end of its body and exhale it at the other (that is what Furahan hexapods do, but not to enable sandswimming). Problems, problems...

You had better make the animal small and give it a low metabolism, so it will not need that much oxygen. Well, someone studied how mole rats breathe (Seymour & Seeley. J Arid Environments 1996; 32: 453-461). The authors did some mathematical modeling and concluded that mammals weighing up to 200 grams could comfortably exist completely encased in loose sand. Mole rats are a lot smaller than that, at 15-40 grams, but that upper limit of about 200 grams does not exactly allow for an impressively large sandworm. Before anyone corrects me, I am aware that Dune's sandworms are supposed to produce oxygen, not use it. But if anyone wishes to create a sandswimmer with a more conventional type of metabolism, this is something to reckon with.

Sandfish disappearing under the surface
Baumgartner et al PLoS One 3(10): e3309. doi:10.1371/journal.pone.0003309

Click to enlarge; Baumgartner et al PLoS One 3(10): e3309. doi:10.1371/journal.pone.0003309

There is much more research going on concerning sandswimming lizards (perhaps they are easier to keep in a terrarium). One species is even called the 'sandfish' (Scincus scincus). Over the last few years people have studied their mechanics and came up with a few interesting results, the main one being how they actually swim. At first there was a notion that they used their small legs to loosen the sand to make it more fluid, allowing them to swim through it by undulating their bodies. These researchers used nuclear magnetic resonance to take a look through the sand. The image above shows such an NMR of a sandfish beneath the surface. As the legend says, the legs are sticking out; but is it at rest or actively moving?

Click to enlarge; Maladen et al. Science 2009; 325: 314-318

Afterwards other researchers went one further and used high-speed x-ray imaging. While diving the animal does use its legs, but while sandswimming it keeps its legs close to its body. Here are some images of how it does so. Above the surface its legs stick out in typical reptilian fashion (C) but they are held back when the animal is swimming (E). The body goes through very pronounced sideways movements in order to move forward a bit; it does not look like an effective means of propulsion at all.

You might think that that is the end of the story, but not so. People actually built a sandswimming robot that undulates just like the sandfish does. That is what the video above shows, along with some more footage of an actual sandfish. There is a nice page at PhysicsCentral with some more data on this particular study.

Compared to a 400 m Sandworm of Dune a 40 gram mole rat or a sandfish lizard are less imposing. Then again, they are real, and I personally find the scientific story of how sandswimming really works just as exciting -in a different way- as a good science fiction story. I can't wait to find out what's next.

Hot Summer on Furaha

2011-03-13T14:10:00.007+01:00

While thinking of new posts, I finally took some scenes I had prepared much earlier and assembled them. I have tried my hand at making animations before (here and here), but will stop doing so for a while. The program I used to to define plants (XFrog), does not allow for a full wind animation, and without that you cannot really animate natural scenes well. Vue Infinite, the program I used to render scenes, can in fact take care of moving foliage quite well, but its plant editor is sadly not open enough to allow me to define interesting alien plants. That is the main reason that this scene depicts a hot day: there is no wind at all. For fairly obvious reasons there are no animals to speak of, or at least none galloping through the landscape. You will need your imagination for that, I am afraid.

When an animation is lacking in movement it cannot work very well. Then again, I did like the way the 'time lapse' scenes came out, particularly the one in which you see the planet spinning during the night. The direction of movement of the stars (straight up) tells you that we are near the equator.

[Later addition: I guess I did not pay enough attention to logic. In the last scene you see the sun setting at a fairly low angle. If we would really have been near the equator, as suggested by the movement of the stars at night, the sun should dive towards the horizon at a more or less right angle...]

Anyway, here it is. There is a large ballont passing by, and look out, or rather, keep an ear out for splatterbugs at sunset.

There is a larger version on YouTube.

The Creatures of Bobby Chiu

2011-03-06T15:46:00.012+01:00

It is quite possible that just about everyone with an active interest in paintings of fantastic animals has already seen the work of Bobby Chiu. If not, well, then I am happy to introduce his work to you. It does not really fit that well with what I normally discuss on this blog: I like a hefty dose of science in my creatures, and Mr Chiu's work does not provide that. But I have made exceptions in the past before (for instance here and here). On looking back at the exceptions I realised that I am never much impressed by fire-breathing dragons and aggressive mean-looking monsters. There are plenty of those to be found on covers of books or on Deviant Art, so it is not a lack of availability. Instead, a sense of humour is more important to me, and Mr Chiu's painting have that in abundance. If you wish to have a closer look, here is his own site, and you will also find him on Deviant Art and on the CG society. Or just try 'Bobby Chiu' on Google.

Click to enlarge; copyright Bobby Chiu

Did I mention that he is an incredibly good painter? Just look at the composition of this one. You really have to know what you are doing in order to lay out your subject in this way.

Click to enlarge; copyright Bobby Chiu

A 'Kangamolerat bunny'. I guess the name says a all: bits of kangaroo, naked molerat and bunny. I do not think I have to point to this cutie's dark side. I love the way the light strikes the rock wall behind the bunny.

Click to enlarge; copyright Bobby Chiu

A Baterpillar Farret. What else?

Click to enlarge; copyright Bobby Chiu

And a 'Big Bad Bunny Eater'. Mind you, there is some serious biology here: the real bunnies are obviously attracted by the fake one, so this is a nice example of 'aggressive mimicry'. Mimicry describes the situation where one living species resembles another one for some purpose. It is not camouflage, in which an animal merely tries to blend in with its environment. In defensive mimicry animals may look like more dangerous ones, which stops them from being attacked. But in aggressive mimicry the predator does the trickery, usually by mimicking something the prey is interested in. In this case, you wonder what it is about the fake bunny that so mesmerises the real bunnies? Could it be sexual attraction? It wouldn't be the first time a pair of pretty eyes led a man/bunny to his doom.

Click to enlarge; copyright Gert van Dijk

All this reminded me that I had once also painted a fictional animal displaying aggressive mimicry. The painting was done when I was about 20, and now, some decades later, it is lost; all I have is a poor black and white image. That is just as well in a way, as I would not dare to compare my painting skills with those of Mr Chiu. But the subject matter does lend itself well to a comparison: somewhat dumb herbivores are lured to a sinister fate by a predator with a cunning plan.

Oddly, both Mr Chiu's predator and mine seem to take a perverse delight in what they are doing. Perhaps there is 'aggressive mimicry' going on at different levels here: the humour hides something sinister, creeping through...

Swimming in Sand II: some facts, more fiction ('Tremors' & 'Primeval')

2011-02-20T13:37:00.015+01:00

The previous post and the appendix dealt with Dune's sandworms, and how difficult it would be to getting millions of tons of sand out of the way to make such animals move. While the hard-boiled scientist in me rejected them as utterly impossible, the somewhat more romantic SF fan, also inside me, decided not to care one bit.

The size argument probably means that any real sandswimmers, by which I mean those on earth and in serious speculative biology projects, had better be small. Are there any other limitations on what they can do? Can sandswimmers dive as deep as they like?

I searched for an answer by looking at the physics of soils. Not surprisingly, the pressure in sand or another type of soil gets deeper the deeper you get, the same as pressure increases with depth in water. Typical soils contain not just grains of sand, but water as well. That complicates matters because there are separate pressures of the grains and the water between them. Luckily we can forget the water component as we are dealing with pure, dry sand. Comparing the effects of depth in water and sand reveals that sand isn't really a fluid.. They have in common that pressures increases with depth, and more so in sand, as it is heavier. But in water the extreme pressure at the bottom of an ocean trench does not stop fish from moving at all, whereas I imagine that movement is impossible under even two (maybe even one) meters of sand. While this seems intuitive, I found no readily available physical explanation. I suppose it has to do with the internal friction between grains of sand.

Click to enlarge. From: Baumgartner et al. Investigating the Locomotion of the Sandfish in Desert Sand Using NMR-Imaging. PLoS ONE 3(10): e3309. doi:10.1371/journal.pone.0003309

Loosely packed sand can be shaken, and then it sort of acts like a fluid. The image above is in fact from a study on sandswimming lizards, in which the authors speculated that decompacting sand might make it more fluid.

Click to enlarge. Copyright Gert van Dijk

But simply adding more sand on top would cause the sand to become impacted, and then no amount of shaking is going to create spare room. That is what is shown here. If something (a sandswimmer!) starts pushing a number of grains upwards, an entire column of sand above needs needs to be shifted. In fact, initially that column might look more like a cone, until the grains start shifting. At any rate this is real work.

What all this suggests is that pressure limits swimming in sand to superficial layers. A consequence of that would be that you would see the surface move when the swimmer is passing. It does not seem likely that sandswimmers can swim up to a potential victim without that victim being aware of the sand apparently moving of its own accord. Obviously, if the sandswimmer is a herbivore, any plants it is creeping up on wouldn't notice that. But sandswimming predators that wish to devour surface-walking prey had better do so from an ambush. Having said that, let's have a look at more fictional sandswimmers.

'Tremors' is a film about monsters ('graboids') that beleaguer a small community in a desert environment. The graboids swim under the sand at an amazing speed. As you can see from the video clip, they do break the soil above them, so the filmmakers gain some points for that. The speed at which they move is ludicrous, I am sorry to say. I couldn't see how the animals move: no bristles or legs or anything else I could find. The scene in which the graboid crashes into a concrete wall is wonderful from a story-telling point of view, but less so from a biomechanical point of view. It's not that the animal wouldn't get hurt, hitting concrete at that speed, but that the packed sand it moves through with ease would in reality provide a similarly unyielding obstacle. Anyone who ever took a failed dive and belly-flopped on water knows how hard water can be when struck at some speed. Now take the same dive on sand: there wouldn't even be a dent in it. The same principle is at work with sand sacks: they stop bullets. So I am sorry once again, but graboids are not feasible as shown. As was the case for Dune, I do not think that this harms the enjoyment of the film in any way. Apparently, the needs of fiction outweigh the needs of facts (Mr. Spock might have said that, but I did). Luckily 'Tremors' has a lot of humour in it, so I feel the same about it as I did with Dune.

The scene above is from a British television series called 'Primeval' in which time portals come into life now and again, allowing past and future wildlife to blunder through and run amok in England. In this scene a villain has captured some Silurian scorpions and uses them to terrorise a beach. The scorpions are a lot bigger than they were in reality and are supposed to be excellent sandswimmers, with lots of long limbs sticking sideways. Hmm; that can't really help their sandswimming abilities. When they approach, sometimes you see the sand move, particularly when the scene require drama to be built up, while at other times the scorpions strike without causing as much as a ripple on the sand.

There is a delectable irony in the Primeval scene. A man has been buried in the sand by his children. This is what people do at beaches, and if you search Google or YouTube, you will soon find examples of people being unable to free themselves, especially when the tide comes in: one wave of water can undo a minute or two of frantic digging by bystanders. In the Primeval scene, the buried man cannot free himself, and through this nicely illustrates that humans are very poor at sandswimming. And then the scorpion swims in, from deep beneath the ripples, and sucks the poor man under. Unfortunately, there is nothing about a man-sized scorpion that would make it a better sandswimmer than its victim. I guess the reasoning was once again that "The needs of fiction outweigh the needs of facts".

Swimming in Sand 1a: Dune appendix

2011-02-12T17:16:00.008+01:00

Strictly speaking this post has no exobiology in it, so has no place here. But I could not resist digging up the only painting I ever did of an existing work of SF, and that was Dune, the subject of the previous post. So here it is. The painting is (shockingly) old, but the lettering is all new.

(Until now New Hades Publishers specialised in nature books -have a look at the Furaha site-, so this must be a new approach for them.)

Click to enlarge; copyright Gert van Dijk

Why no sandworms? As I said before, for me Dune was about people foremost, and sandworms second.

Swimming in Sand 1: the Sandworms of Dune

2011-02-05T14:19:00.019+01:00

Sand is an odd material. In some ways it is like a fluid, as you can scoop up a handful of it and let it run through your fingers. Still, hills and dunes of sand will hold their shape, which water cannot do. You also cannot stand on it, and if you are buried underneath even a few decimetres of it on a beach, you will find it is much more resistant to movement than water is. Some animals 'swim' in it though, both real and fictional ones. There seems to be enough material for more than post, so this one is just the first. To start, let's begin with SF's biggest sand swimmer.

Click to enlarge; painting by John Schoenherr

This is Shai-Hulud, the sandworm of Arrakis, the spice planet! These paintings are by John Schoenherr, a brilliant SF illustrator who died in 2010. Sandworms started life in Frank Herberts's Dune, an SF classic. I loved it when I first read it, several decades ago. I think I read the original novel more than once, but cannot say the same for the sequels, of which I may have read two, or perhaps even three (I tend to dislike trilogies with more than three volumes).

Much has been written about just about any aspect of the Dune books, and the sandworms are no exception. In fact, there is an entire book devoted to 'the Science of Dune', and one chapter was devoted to 'The Biology of the Sandworm'. You can download that chapter for 1 US $ here. I liked it, as it explored sandworm biology by comparing it with Earth biology. Sybille Hechtel, the author of the essay, had this to say about sandworm movement: "Herbert never describes precisely how the worm moves, only that it looks like a fish that 'swims' just under the surface. He frequently describes the worm’s motion in sand as 'a cresting of sand,' or mentions the 'burrow mound of a worm'. The worm primarily comes above the surface when it’s eating a ’thopter or crawler, or when the Fremen catch one and put their hooks in its scales to drive it up out of the sand." Well, that means there is no information whatsoever in Dune about how sandworms move. Starting with the word 'worm' there seem to be two major Earth modes of movement to compare it with.

Earthworm movement; click to enlarge; copyright Gert van Dijk

The first are earthworms. These move in an ingenious way, as the segments of their bodies can change shape: when they are short and wide, they press against the soil and anchor themselves to the soil. Any segments behind them that are long but narrow can be pulled up by shortening them in turn. The beauty of the system is that any segments in front can be pushed forwards by narrowing them. In this way, shortened segments function as anchors for thinner segments in front and behind. I have no idea whether or not sandworms are supposed to move like this, but one thing is certain: to move forward, earthworms have to force the soil aside to make room for their body.

Undulation; click to enlarge; copyright Gert van Dijk

The second way is by undulation, that way snakes, eels, and lots of Earth fishes move. the body moves in bends, and each bend pushes against the material around it. Those forces have sideways (blue) and backwards (red) components. The reaction forces of the material push the animal forward. Again, one thing is certain: whether in water or soil, the animal has to push that material aside to make room for its body in front of it.

So however sandworms move, they have to make room for their bodies. There are only two ways to do that: if the stuff around you is compressible, you can compress it, and otherwise you have to shift it. Water is almost not compressible at all, and sand doesn't compress well either. That leaves shifting it, and the only direction to shift it in is upwards, which sounds like a lot of work. Moving aside water is fairly easy; the fact that the largest animals on Earth, whales, live in water proves this. But the energy costs of shifting sand upwards are probably much higher, something that will probably recur in future posts.

Sandworm scale; click to enlarge

One thing is certain: more sand means more work. So how much sand must a sandworm shift? Well, the biggest sandworms are supposed to be 400 m long with a 80 m diameter. That is big. Very big. In fact, that is longer than a US aircraft carrier (only 333 m) and in the same league as the biggest super oil tankers (458 m). The Wikipedia page on tankers had a very nice scale drawing showing that tanker as well as some of the world's largest buildings, to which I added two sandworms: a puny 200m one and a fully grown 400 m one.

The clip above (taken from YouTube) is from the 1984 film adaptation, and nicely conveys the scale of the worm. Also look back at the paintings and look at the humans, giving a sense of scale. If such an animal is to move one body length forward, it will have to displace the volume of its body in sand. Assuming a completely cylindrical body, the volume of a 400 m sandworm comes out at a bit over 2 million cubic meters. I found figures for the mass of various forms of sand. The lowest density concerned loose sand, so let's use that. One cubic m of loose sand has a mass of 1442 kg, so the mass of the sandworm's volume in sand is 2884 million kg.

I hope these numbers convey the nerve Herbert had in thinking up such a monster. I must say that they impressed me. Regardless of whether a sandworm moves like an earthworm or undulates, displacing all that sand is serious work! Aircraft carriers run on nuclear reactors, and supertankers take ages to turn around. That is in water, a much more forgiving medium than sand. Simply pushing against sand with big muscles isn't going to do the trick. In this respect it is intriguing than no illustration of a sandworm I've ever seen shows anything in the way of a propulsion system. No limbs, no bristles, no segmental thinning, nothing. That goes for paintings well as the film and TV adaptations. Perhaps there are workarounds...

One solution would be to give Arrakis, the sandworm's planet, a very low gravity: moving the sand would still require overcoming its inertia, but at least it would weigh a lot less. But reducing gravity has other effects: humans on Arrakis could jump around a lot, but the story doesn't mention that, so that's off.
Perhaps the sand could be made lighter? The website I mentioned above states the density of lots of materials. Powdered carbon only masses 80 kg per cubic meter, and pulverised kaolin (china clay) weighs in at only 352 kg. Better, but still...
Perhaps the friction between grains of sand can be reduced, but you wonder whether that is possible while still allowing people to walk around on sand.
Are sandworms hollow cylinders? If so, then the sand inside their bodies could more or less stay in place. That would reduce the volume needed to shove aside. Perhaps their large size is a way to enlarge area without necessitating a large volume; who knows. It would not do wonders for friction though.

I am afraid that the only way out is to use a lot of 'handwavium', which basically means not worrying about the impossibility of sandworm movement. After all, suspension of disbelief is what keeps SF going. Does this make Dune a silly book? Not really, I think. I liked it very much when I first read it, and countless others did and still do. I only get irritated when authors or film makers pretend to be accurate and then blatantly are not. It is like the difference between someone who says he can bend spoons with psychic powers and someone who won't tell you how he does his tricks but acknowledges that they are tricks. Sandworm movement is such a trick...

It's a 'Fish'!

2011-01-22T10:47:00.010+01:00

One of my good intentions for this year was to cut back on blogging. I did have my doubts whether this was really a good idea, as I like writing. Still, blogging keeps me from painting, and I had been postponing that for too long. I had decided to switch from brushes and artists' oils to digital painting about a year ago, but my first attempts proved a shock: I was used to applying paint where I saw the tip of the brush, and now there was a large distance between the graphics tablet and the screen. There were other mishaps as well. Even after changing Photoshop for Painter (more on that here) I still procrastinated, until I put aside enough time to really play with the brushes. Once I managed to forget what I was doing, my visual and motor skills, such as they are, met again and renewed their friendship. To make a long story short, here is my first digital painting I feel I can show the outside world. It's a fish. Sort of.

Click to enlarge; copyright Gert van Dijk

To be more precise, it is a Fusus rostrauctus of the Clade Fishes IV (Proculcapiti). I may have to check naming conventions here though. Anyway, I revealed a glimpse of Fish evolution previously, which I will not repeat. You may observe the typical traits of the Clade, but I will focus on artistic matters here (just as well, as there were some sudden changes in their anatomy compared to the rough sketch in the earlier post!). Having done a fairly large number of full paintings in oils for the eventual Book, I felt I needed additional illustrations, highlighting individual species, cladograms, things like that. This is the first of those. I wished to keep the painting style more or less the same as that of my previous oil paintings, and think I managed. After messing about with Painter's very large assortment of brushes, I settled on just two, and used those throughout (for those in the know, I used a detail oil brush and a blender, but tweaked size, opacity, 'resaturation' and 'bleed' continuously).

Just for fun I will show some layers of the final painting. The nice thing with digital painting is that you can use layers of colour that stay separate, so you can go back to a deep layer even after you painted others over it. In a 'real' painting ('physical' painting?) the only way to correct a deep layer is to scrape it, and everything on top of it, away altogether.

Click to enlarge; copyright Gert van Dijk

So here is the start of my project (it's not a tutorial: I'm not good enough for that). I started with a rough sketch and simply changed lines and shapes until the concept became more or less ready; that is the image on the left. I then drew a much neater line drawing on another layer, and used that as a guide for the painting job: the one on the right. In old times, I would have done exactly the same, but using various sheets of paper for the sketches on the left and one sheet of transparent paper for the one on the right.

Click to enlarge; copyright Gert van Dijk

After that you start painting. In this case I chose flat colours to start with. With oils, this basic colour layer would have obscured the line drawing on the board. Digitally, things are different: you can paint underneath your sketch, so that stays visible. Very odd at first, but extremely useful. The base colours are on the left, but without the line drawing. After that, another layer was added (on the right), and that is where it becomes interesting: that one modifies the base colours with shadows and highlights, as well as with some subtler colour changes here and there.

Click to enlarge; copyright Gert van Dijk

After that I decided to add another colour layer (I should have done that before, but, as I said, I am new at this). The rest comprises adding some reflections, details, some final shadows etc., and there we are. Mind you, the original is almost 7 times bigger, so some detail is lost. Anyway, here's my first digital painting. I hope you like it.

Birds with clubs and other smashers: clavigerism

2011-01-08T13:02:00.013+01:00

I intended to write just one blog entry every two weeks this year, and am already breaking that rule. I could not resist, after reading a paper on an extinct Terran bird. The similarities to some Furahan creatures were simply too interesting to leave it alone, so there you are.

The bird, a flightless ibis, was described in a paper entitled 'The bizarre wing of the Jamaican flightless ibis Xenicibis xympithecus : a unique vertebrate adaptation' (Longrich NT, Olson SL; Proc R Soc B 2011, online 5 January 2011).

Click to enlarge; Longrich NT, Olson SL; Proc R Soc B 2011, online 5 January 2011

And here you see a reconstruction of the bird (top) and a comparison of its wing bones (bottom) with that of a still living ibis species. The authors make a case that the bird was flightless, and go on to say that the wing bones are odd for flightless birds. That holds for the hand in particular, with its thick and curved bone. The authors think it functioned as a club, and provide various anatomical reasons why they think so. After that, they discuss the club some more:

"We therefore propose that the wing of Xenicibis functioned as a club or flail. Several features of the limb would have facilitated this function. Kinetic energy is the product of mass and velocity squared; accordingly, weapons such as clubs and flails have a long handle to increase the angular velocity of the club, and are heavily weighted to increase the mass accelerated by the swing, and the centre of mass is near the end of the club, where the angular velocity is highest. Precisely this design is seen in the hand of Xenicibis, where the end of the wing is massive, and the proximal metacarpus and long forelimb could act as a handle. "

The authors of the paper also compare this odd ibis design with the front legs of mantis shrimps (Stomatopods), that function in a similar manner. The video above shows a slowed down version of a strike, and incidentally allows the shape of the club to be appreciated as well. It is taken from the lab of Sheila Patek, whose work on the biomechanics of their legs featured in this blog previously.

Click to enlarge; copyright Gert van Dijk

A long time ago mantis shrimps were the inspiration for Furahan neocarrnivores. You will find more material on them on the Furaha site (go to the land page). One of them is shown here (one of its commoner names is 'pugile'). Compare its front legs to those of mantis shrimps and to the ibis; I think that the ibis still had a long way to go before its clubs measured up to those of other club bearers. Then again, they were probably meant to hit other ibises, not kill prey animals, and it might not be advantageous in the long run to kill fellow ibises; merely sending them off might be good enough.

Stomatopods, Xenicibis and Furahan neocarnovores may all be said to have developed their clubs from what originally were locomotor limbs. In the Stomatopod and Neocarnivore cases, the limbs in question were used to walk with, and in the Xenicibis case its ancestors used them to fly with. In all cases their freedom from locomotion opened the door for a new function, and interestingly the new function was a weapon in all three cases. I think that Xenicibis therefore qualifies as much as the other two as an example of 'centaurism' (more on centaurism here and here).

I am delighted that we now have an example of 'raptorial centaurism' concerning a fairly large animal on Earth. Both Stomatopods and Furahan Neocarnivores have evolved various kinds of front legs, functioning as different types of weapons: there are 'smashers' and 'spearers' in both cases (Neocarnivores have webs or basket-like thingies as well). It would be great if more diligent paleontological work would uncover a 'spearer' on Earth as well, but I will not hold my breath. Meanwhile, perhaps it is time to coin a phrase to start differentiating between the various kinds of weapons limbs may turn into. 'Smashers' sounds good, but is limited to English, and that won't do. Luckily we still have Latin. A 'claviger' is an existing word for club carrier, with the plural 'clavigeri'. Turning it into a principle would result in 'clavigerism'. I don't expect a follow-up paper on Xenicibis to use the word; then again, the authors used the interesting phrase 'volant species' for birds that actually fly, so perhaps they can appreciate a bit of biogeekery...

Nereus (or how you can have radial flight with an odd number of wings)

2011-01-03T22:13:00.012+01:00

As regular readers know, I am always on the lookout for creative projects concerning speculative biology. On places like Deviant Art you will find many interesting alien or alternate animals. Some feature new traits, others rework well-known themes; some are professionally drawn, others are less so. But what interests me most if there is a background: are there biotopes, is there a food web, do the predators match the prey, etc. That shortens the list considerably.

Some large projects have been in existence for very long times, and it does not feel entirely right to discuss them here. But there is one project, Nereus, that is relatively new. Its creator, Evan Black, does not mind, so that helps. Apparently Nereus received its name because humans first thought it was a water world (Nereus is a being from Greek mythology). The earliest post on the Nereus project on the Speculative Biology forum dates from May 2009. Evan has already produced 100 species and aims to achieve no less than 200 species. That is a lot or work: creatures have to be designed and described, and also drawn. I like the way Evan draws animals: while a bit stylised, they are very energetic, and as design they work: what you see are lively animals.

Click to enlarge (VERY much so!) Copyright Evan Black

Here is a start: a rather large cladogram of current Nereid species. Don't be surprised to find that the one on Evan's site differs from the one here, because he might have added a new species by the time you go there...

The Speculative Evolution pages contain discussions and comments on how Nereus develops, but I much prefer to see the result on Evan's own site. There, you can work your way through the menu, clicking on the Latin names of the various groups until you get to individual species, but you do not see what you are aiming for until you get to the species pages. Once there each species has two pages: one with text and a thumbnail, which leads to a much larger image with additional text. But there is another way to browse Nereus that I much prefer, and that is to choose 'world', and then 'cartography and climates'. That will take you to a list of 7 biomes, and clicking on them rewards you with an overview of that biome and small images of the species in it, that you can then pick and read at will.

Click to enlarge. Copyright Evan Black

As an example, here is the 'Sog Basin'. Sog "carpets the landscape like a thick tangle of spongy red veins", which sounds a bit like Well's Martian weeds. Luckily, there are no intelligent aliens around to regard Earth with envious eyes (or not yet). Sog sucks up water from the few available sources, and transports it across the otherwise dry biome. Leaks in the sog create watering holes, on which many species depend. Now that is why I prefer creations with a background: you immediately start to think how that works, how such species might look, etc.

Click to enlarge. Copyright Evan Black

Here is one such species: the kappa (Nothorana pratensis). It is a predator lying in wait in sog ponds, with just its dorsal eyes and its nostrils above the water. Take a good look: the kappa has three legs: two paired front ones and one unpaired jumping leg in the back. The illustration also contains a classification list containing the familiar Linnaean scheme, which starts at the species level and goes all the way up to the phylum Tetrabrachia (that would be 'four arms', if I remember my Greek correctly). One of the nicest things about Nereus creations is that it all fits together. Look up the Tetrabrachia, and you will find a page devoted to their anatomical Bauplan.

Click to enlarge. Copyright Evan Black

And here it is. The four arms in question concern four major nerve trunks emerging from the central brain. One trunks goes upwards, and that one deals mostly with sensory functions, which in modern Tetrabrachia has caused them to develop a head. The other three trunks control movement. In effect, what we are seeing here are radially organised animals, and I like the idea of taking radial animals rather further than they have managed to do on Earth (see the discussion on tetropters here, here, here and you can more on tetropters yourselves; here is something about radial symmetry; if that is not enough, just search for spidrids on this blog). But the kappa does not show radial symmetry; it is blatantly bilaterally symmetrical, and the legend includes information just when that happened.

Click to enlarge. Copyright Evan Black

I cannot resist showing one particular specimen, and that is because Evan and I discussed its s flight mode. Again, this is a radial life form. Most flying forms on Nereus are bilaterally symmetrical, resulting in flight plans that are superficially similar to the ones on earth. Not so the Cliff Whistler (Cadosmilos Aetopsis).

As you can see, it flies a bit like my tetropters. The tetropter discussions may have helped inspire the Cliff Whistler, which is flattering. Anyway, the Whistler flies by beating its three wings horizontally to and fro. Diehards out there may remember that I made extensive use of the 'clap-and-fling' principle to explain tetropter flight. The 'clap' involves two wings beating against one another at the end of their movement, then sweeping back to the other end of their range, where they then clap against another wing. Etcetera. That works with two wings (Terran insects and some birds), four wings (Furahan tetropters) and would work with more wings too, although no-one has yet invented any of those yet as far as I know. Besides offering increased lift through 'clap-and-fling', an even number of radial wings neatly solves the problem of torque: if a wing moves clockwise it pushes the body counter clockwise, which is useless. With two or four wings these forces even out.

Three-winged radial flyers run into problems. There is no clap-and-fling mechanism, and the wings move in unison: all three clockwise, and then all three counter clockwise. That leaves torque to be solved. Well, evolution, in the form of Evan, designed an adaptation of the Whistler's mouth parts at its bottom: these evolved into winglets beating in the opposite directions of the main wings, countering to a degree. Enough for the Cliff whistler to be a viable organism, or so Evan and I thought.

Recently I came up with a way to have a clap-and-fling mechanism with just three wings though. It would increase lift but introduce some new problems. Again, Evan and I thought that it might work, but not necessarily better than the Cliff Whistler approach. Perhaps one species will emerge on Nereus with this particular mechanism, we would have to ask Evan. I am not going to tell you how it works, merely that it can be done: each of the wings A, B and C claps against another wing on the extreme ends of its movement range. I wonder if anyone will take the bait...

The woolly-haired Shuffler: Splendid Insulation

2010-12-23T21:32:00.005+01:00

It is cold outside. Then again: there will be a white Christmas, which is largely nice. All that snow led me to choose a wintery scene for my long overdue update of Furahan animals. The update follows the same pattern as previous ones: if I show a new animal, an old one leaves the scene, and that is exactly what has happened. After all, if the Furaha Project is ever to become a book, there should be things in it that are not freely available on the internet.

Click to enlarge; copyright Gert van Dijk

Here is part of the map of Furaha showing the usual covering of snow in Winter for the Northern hemisphere. This is part of the area where the woolly-haired Shuffler lives.

Click to enlarge; copyright Gert van Dijk

You will find the Shuffler on the land page, but here it is again. I could not resist adding some additional information here. At first glance you may wonder where the woolly hairs are, as the animal looks somewhat naked. Well, the hairs are underneath.

There are various ways in which animals can combat heat loss in a cold environment. Behavioural solutions are to stay indoors or sleep through the winter. There are anatomical tricks as well; a good principle is to be as round as possible with as few protruding parts as possible, in order to get a small surface area for a given volume. So, expect small ears, short tails and thick legs for animals in cold climes. A second anatomical trick is to be large, as it is easier for a large animal to conserve heat. There are metabolic and circulatory tricks as well, but a good theme is insulation. Layers and layers of fat wrapped around the more costly parts of the body will help, and as an aside these can store food as well. One of the best insulating materials is air. Fur works because the hairs trap air near the body, preventing the freezing effects of wind to reach warm parts of the body. Fur on Earth works quite well, and various animals have such sophisticated fur designs that they can withstand horrible conditions. Just consider hair that traps sunlight, leading the warming radiation into the body; hairs that are fairly thick but hollow, so they trap even more air; or consider fur made of layers of hairs with different characteristics. But such furs can still get wet, and while even that can be solved -think of polar bears- there is another way to protect against wind chill, and that is the ways humans do it.

Humans? Naked apes? I am talking about clothing. Animal pelts must have been among the first items of clothing, and among women of a certain class, a certain age and a certain cultural background fur coats are still in vogue (I cannot help but think -and sometimes say- that all fur coats are second-hand clothes, and that they invariably looked much better on the first owner). Fur coats work, but modern polar clothes are a miracle of ingenuity. They invariably have fibres to trap air much as hairs in furs do. But there is usually an outer layer of wind-breaking material to stop the trapped air from mingling with the really cold outside air. Animals don't have that, for the simple reason that it would not be easy to enclose large areas of air inside the body (oh well, Furahan tetrapterates do, but that is another story).

Once again, humans solved that particular riddle. Some brilliant Eskimo / Inuit must have realised one day that coats made of fur work even better when you wear the furry side of the pelt against your skin instead of on the outside. That was a stroke of genius, I think, but it is not listed among other great humans inventions such as fire, wheels and gossiping (the probable reason for the evolution of speech). I expect that women who like fur coats do not know this, and suspect they would ignore it anyway.

That Eskimo's idea is behind the fur coat of the Shuffler. Its skin forms folds, and the inside of the fold is covered in woolly hairs, while the outside is devoid of hair. The fold is dead, in fact. This might be as near as the 'Eskimo Invention' as biological evolution can get starting with hair on the outside of a body. The main downside is that investing in large amounts of skin and hair for just one season's worth of protection is costly in metabolic terms, so I played with alternative ideas, such as letting them keep their folds all year. Or perhaps they eat the skin when it falls off, in a rather unappetising manner.

---------------------------------

As you can see, I made some other changes to the web site as well:
I added a new book, on Warren Fahy's 'Fragment'. This is probably the only fake book in the entire New Hades catalogue of fake books that will one day likely be turned into a real book!. It is on the book page, of course.
The list of links has been reworked too, see the 'about' page. Snaiad is gone, but I will put the link back again when Nemo chooses to find a new host. Then again, Nereus is there now...
The illustration on the site's front page has been changed as well; no new items there, but I think it looks better now.

Finally, I have written too many posts on this blog: it keeps me from actually painting new Furahan life forms. Next year, I will probably reduce the frequency of posts to perhaps once every two weeks. We'll see. I do have some ideas for good subjects though. Meanwhile, please consider telling all women with fur coats, except for the ones you really like -the women, not the coats-, that they should wear their coats with the fur on the inside.

Furaha on io9

2010-12-10T16:47:00.006+01:00

A few days ago this blog was mentioned on io9, under the heading Mad Science. The article was entitled "An intensive, multi-year study of realistic alien life". There was a definite spike in the number of people who visited my sites afterwards. Welcome new readers!

I was a bit doubtful about the 'Mad Scientist' bit, but what can I say? There is some truth in it; after all, I have been known to work my way through texts on the optical limits of compound eyes, to see whether I could somehow get around the conventional thought that such eyes would have to have a diameter of one meter to obtain a resolution as good as the human one. Is that geeky? I now think that computer science might hold an answer, and if you want me to write a post on that subject, you know what you are...

All right, I admit it: such activities might conceivably be considered geeky by some. In fact, according to Annalee Newitz, who wrote the post in question, my blog is "a treasure trove of biogeekery". Now that is a word to remember. Annalee must be a related soul, as she wrote: "This kind of intense, charmingly maniacal worldbuilding warms the screaming void at the center of my nerdy heart." Well, Annalee, it's nice to be appreciated, and please come again if you need rewarming!

An xenobiological conference call

2010-12-08T21:01:00.009+01:00

Just a short post this time. If you read this blog, it is a safe bet that you are interested in speculative biology, astrobiology, xenobiology and/or exobiology. I mention all four terms as they are about more or less different things. 'Speculative biology' seems to stand apart from the others; it is about any kind of biology that is not about real living beings, here, there, then or now. It can be about alternative evolution on Earth, such as dinosaurs in the present or about evolution on Earth in the future. Xenobiology, exobiology and astrobiology are restricted to unearthly life. The words 'exobiology' and 'xenobiology' are clearly older, but the newcomer 'astrobiology' seems to have won the day. Personally, I prefer 'exobiology', in part because it evokes 'exotic' and in part because I am linguistically conservative. 'Xenobiology' literally refers to the biology of 'strangers', and so it comes very close, etymologically, to 'alien biology'. 'Astrobiology' is literally about life on stars, and while I am willing to listen to any hypothesis about life, life on or in stars seems unlikely. But I will not be difficult about this; after all, 'astronomy' deals with more than just stars. Essentially xeno-, exo- and astrobiology are all about the same subject.

So, would you wish to go to a xenobiological conference? The full title is '18th International Congress of Xenobiology and Planetary Biology'. The program looks interesting: there will be talks on topics such as 'Xenophages and other new treatments and their impact on Human physiology'. As if Earth viruses and bacteria aren't enough, modified or with their wholly natural charm, you can now get treated with alien organisms. It's completely harmless, really! The introduction of Earth lifeforms in alien ecologies is always good for a controversy, so the talk on 'Introduction and Establishment of Terrestrial Insectoids in Rigel Kentaurus' is bound to draw a large audience. Then again, what do we care about Rigel Kentaurus?

You can read more on the conference on the following website. You will have to be patient though, as the conference will be held on 16-21 September, 2206. Aha; while there are serious conferences on astrobiology, this one is fictitious. The website is beautifully made, and if you ever been to a scientific conference, you will know that this is an excellent parody. It is all there!: there is a social program, a timetable, information about the venue and the hotel, and a list of sponsors. Whoever made this knew what he or she was doing. The author can be found by stripping the web address, and that yields something else altogether.

The website is in Finnish, a language I can recognise but not understand. Luckily, there is a copyright name there: credit to whom it is due, which in this case is Sampsa Rydman. If you work your way through the various options in the menu, you will find some interesting ones. One definitely worth a visit is 'Xenobiologia', proving that some Finnish words are easy. But from then on I would advise you to use Google's translation services. You will find a page with interesting pencil drawings on it, of which I will show two.

Click to enlarge; copyright Sampsa Rydman

This creature is a Löyhkähaahkaja. So what does Google make of the accompanying text? Here it is, without embellishments: "This is a great size (4-5 feet), carnivorous plants attract prey lemullaan intolerable. Although it elääkin entire life rooted in one place, its great tarttumaelimellä a wide freedom of movement. Löyhkähaahkajat spread and multiply rihmajuurakkoaan along."

Well, reading that definitely evokes a 'sense of wonder'. I think that we are looking at a sessile but mobile life form. Other life forms on the page seem to have elements of plants as well as animals, a feature they share with Furahan mixomorphs. The limits of sessile life forms perhaps deserve a post of their own, some day.

Click to enlarge; copyright Sampsa Rydman

And this is a Haaskahyppiäinen. "The kolmeraajaisten hyppiäisten sect belonging to the plains inmate is about 20 cents higher, munimalla growing insect-like vikkeläliikkeinen hajoittajaeläin. They are found largely blue-green leaves and raipparepsukoiden hills and mustaruohotasangoilta."

Right. I thought as much. But look at it: it appears to be a triradial life form, and I have a definite soft spot for radial animals, particularly ones with complex motor skills.

Have a look at the other animals yourself. They are probably more graphically pleasant than biologically plausible, but every once in a while that is admissible. Mind you, if you wish to have a look at the other pages, turn off the translation, or else you will not see the illustrations on the pages. There is a nice planetary map here. I rather liked the images advocating 'robot equality'. I hasten to say that I do not object to treating robots humanely (of course not!) but I hope that does not mean they fall under the heading of 'speculative biology'. Dear me.

I will keep it at this. This is a nice site! I would have liked to have seen more animals, but I guess I will have to wait for the conference...

Walking without Legs

2010-11-28T11:41:00.017+01:00

Pardon? Is walking without legs possible? Well, if you stretch the definition a little...

There are quite a few terrestrial animals on Earth that have no legs; earthworms, legless lizards and particularly snakes come to mind. These are not evolutionary misfits whose leglessness will be their doom any day now. Snakes have been around for some 150 million years, after all. Limblessness in legless lizards seems to have evolved at least 8 times, also suggesting that 'not having a leg to stand on' is not necessarily a bad thing. It is probably a very good thing if your life style requires moving around in confined spaces where legs might hold you back, such as underground, in very dense growth and probably in crevasses between rocks. In fact, you may well wonder whether legless animals might be universal, found on many worlds across the universe.

If so, would all 'serpentiformes' or 'ophimorphs' (take your pick) move in the same way? That is debatable, as there may be one or two possible gaits that do not seem to be in use on Earth. How do animals without legs move on Earth? There are animals whose body length can vary, such as earthworms, but let's only look at those with a fixed body length, such as snakes. You can find more on that using Wikipedia etc., but here is a short summary.

The internet did not let me down in a search for interesting material. In the past I have found that some of my biomechanical ideas to design interesting life forms had also been invented by others designing robots, such as tetropters (radial flyers). In this case it was the other way around, and I came across a mechanical invention that might perhaps be 'biologified'. I found it on the website of the biorobotics laboratory of the Carnegie Mellon School of computer science, where they have lots of interesting material on the design of robotic snakes (there are other robot snake designers, but this site seems to cover all aspects).

Click to enlarge; copyright Gert van Dijk

Click to enlarge; source here

The basic element of robotic and live snakes is a segment (vertebrates are just as segmental as arthropods; the segments are just less apparent form the outside). In the picture above each segment is connected to the next with a universal joint, allowing movement up and down and sideways. The robotic snakes seem to have joints with just one axis of rotation (either up-down or sideways), but these alternate on consecutive joints. There is no movement along the longitudinal axis of the segments. Well, in animals there is almost always a bit of leeway, but not a lot; it's certainly not as if a segment could rotate 10 or 20 degrees along a longitudinal axis. It is tempting to adapt the design to allow more longitudinal rotation, and it would increase the 'alienness' of the design. (We need a word to describe how 'alien' an animal is compared to 'life as we know it'; 'alienosity'?)

Anyway, Earth's snakes can move in various ways. There is the 'rectilinear' mode, in which a bit of skin on the belly of the snake is lifted, moved forward, and put back on the ground again. The next bit of skin does the same thing but slightly out of phase, so you end up with a wave of skin rippling backwards along the belly of the beast. As the ripples push against the immobile earth, the snake moves forward. Think about this: part of the body, while lifted from the ground, swings forwards with respect to the centre of gravity of the body, and when it is on the ground it swings backwards: that is a description of what a leg does, if not what a leg is. A fine distinction, but an interesting one: do you define walking by its functional characteristics, or by the body parts that carry out the function? I tend to prefer the first option, but the consequence would be that snakes walk, and that departs too much from common use of 'walking'.

A very interesting snake gait is 'sidewinding'. Here, the snake lifts an entire segment of its body from the ground, moves it forwards, and puts it down again. You get the picture: a walking analogue again. The robotic snake does it too, with waves travelling down the body both in the up and down and sideways directions. In real life it is quite difficult to get a good understanding of how this works using just diagrams, but the videos shown here might help. Sidewinding provides snakes with their fastest way of locomotion: it is the 'running' of the snake world.

Now we get to the creative part: a gait snakes do not use. The robot's body is moved into a curve, so it lies in a plane. Now imagine that you change the direction of curvature a bit, so both ends of the animal would be lifted from the ground. That is not going to happen, as the uplifted ends of the body will fall towards the ground. The result is a C-shaped curve that rolls forward, a bit as how you would move a log by rolling it over the ground. I was struck by the creative beauty of this solution.

But before people trot off to design rolling metaserpents for their own worlds, they should think about why Earth's snakes don't do this. Rolling along the longitudinal axis of the body will cause the animals' head to spin quite literally. The poor animal will have difficulty in keeping its bearings. Regular readers may remember that there was a similar problem with cernuation. I wouldn't say this form of locomotion, which the robot designers called 'rolling', is impossible for animals, but the animal better have very sophisticated vestibular and equilibrium systems. Alternatively, or additioanlly, the head could do its own counter rotation, in the same way cernuating animals could temporarily keep their head still. Spinning ballerinas also rotate their head opposite their body to keep it still in space, and they are not alien (perhaps a tiny bit).

Here is another example of what 'rolling' can do: the designers have actually been able to make their robot climb a tree! Spectacular, isn't it?

And finally, a robot that is not very prominently displayed on their site. They call it the 'skin drive', and about the only information is that it uses its entire skin to move. From looking at the video, it seems to have flexible rubbery skin, and underneath that there must be series of elements that can be stuck out radially and retracted again. I guess that waves of extraction and retraction march backwards across the body, as if you would push successive fingers against a sheet of rubber. If these fingertips find enough traction against the ground, they will stay in place, and the body as a while will be pushed forwards. It is a bit like 'rectilinear' snake movement, but not exactly the same. I wonder where the inventors will take it, or where its evolution will lead to.

Furaha Swamp Scene II

2010-11-14T11:46:00.010+01:00

If this scene looks a bit familiar, that is because I posted previous versions of it as well, in November 2009. This version is updated though, and so is still worth viewing, or so I hope. The end is a bit rough: the 'Fish' is visible for a short while only, which is intentional, and so I thought I could get away with a limited amount of detail. There is a better quality version on the site: simply go to the plant page and select the arrox tree.

Click to enlarge; copyright plant image Gert van Dijk

Here is a short 'making of'. The plants were all designed with XFrog, a program aimed wholly at structures that branch and grow, i.e., plants. The various rules and settings can be quite complex, but it allows very good control over the characteristics of any plant you create with it. There are not many good plant editors about. One of the few other candidates is the plant editor inside Vue, but that is unfortunately geared towards changing and mutating existing plants, and does not allow the creation of a plant from scratch. Vue has the advantage that it allows its own plants to move in a breeze, which certainly adds to the liveliness of a scene.
The image above shows one of the flowering plants in the swamp scene, as it looks inside XFrog.

Click to enlarge

The next stage is to produce a suitable environment, for which I use Vue Infinite. Basically you start with a 'terrain', which in this case is the ground with some grooves in it to hold streams. Vue allows the user to define 'ecosystems' as collections of 3D objects that are placed according to rules. For instance, one such system could be limited to high points in the terrain. In this swamp scene the arrox trees only grow on such relatively high ground. The marsh growths, with reeds etc., are limited to medium height zones, while in this case hardly anything grows in the lowest ones. That is on purpose, as they would be obscured by muddy water anyway.
Once the playing filed is ready, the camera is set to fly through the scene, and to produce a ray-traced image 24 times a second, or more. A simple scene lasting 4 seconds may take about 10 hours, so a short film of one minute takes many nights of lonely processing (for the computer, that is; I will be asleep).
And then it is a matter of turning the individual frames into films, for which I use VirtualDub. The resulting clips are much too large to show on the internet so they have to be compressed, at the loss of quality. Adding sound and titles adds to the fun, for which I use Adobe's Premiere (Elements).

And there we are; a Furahan scene that does not actually look that alien. One reason for this is that plants may yield less obvious visual 'alienness' than animals. Regardless , I could not resist putting in an animal at the end. a specimen of a 'Fishes IV' species. I do not yet know how to make the parts of their body move, something that would add greatly to the visual quality of the film. But this is the level of my animation skills at present. I do not think that I will try to become good at it, as there is too little time for that.

Click to enlarge. From left to right, typical examples of species from the Fishes IV, V and VI groups. Copyright Gert van Dijk

But I guess that some of you will want to know more about the various 'Fishes', that are just called that by Furahan people because the word came easily, not because it is biologically correct. In this sense the early Horizonists seem to have gone for the old custom of labelling just about any type of water animal a 'Fish'. 'Crayfish' and 'starfish' come to mind as well. I will not go into the early development of Fishes I, II and II, that follow one another in geological time. Not so for Fishes IV, V and VI, shown above in a rough sketch. Here is a quote from an authoritative source, Nyoroge's "Broad Stokes":

"From this point on hexapod evolution becomes more complex. ‘Fishes III’ gave rise to three new groups, ‘Fishes IV, V and VI’, all of which had three pairs of fins. This has caused a great deal of confusion. There are two schools of thought trying to explain the ‘Fishes III Division’, as the debate has become known. The ‘Hexaphile School’ holds that Fishes IV, V and VI evolved separately from multifinned ancestors, and have three pairs of limbs in common, because three pairs of limbs are innately superior to any other number, without actually explaining in much detail why this should be the case. The ‘Monophyletic School’ contends that all three groups have three pairs simply because they all stem from a single ancestor. This is somewhat surprising in view of other differences between Fishes IV, V and VI, which do not suggest a common ancestry. The ‘Contingency View’, which has been gaining strength lately, holds that there is no innate advantage in any number of limbs, and that all three groups have the same number of limbs by accident. Molecular Cladisticians keep silent about the matter, due to a lack of clear evidence one way or the other."

Radial Robots

2010-11-02T19:52:00.023+01:00

'Radial robots'; for a title that isn't too bad. I was tempted to add words with 'r' such as 'rampaging' or 'ravaging', but I resisted, as that ran the risk of rather ruining the effect, rendering it ridiculous.

Back to the matter at hand. When I first thought of a radial walking pattern, resulting in Furahan spidrids, I was content to visualise the gait by writing some programmes in Matlab. The results are shown on the Furaha page, and some were featured in the blog as well (here and here). I never imagined I would see really see spidrids walk. Literally, of course, I never will, unless creative bioengineering kits become available quickly, which is unlikely. But walking robots have emerged on the scene since I thought of the spidrids, and among them radial leg designs, as opposed to bilateral symmetry, seem to be quite popular. You can even buy kits to build one yourself. As these designs probably evolved independently, it is interesting to see how parallel these forms of evolution have become: convergent speculation? I therefore surveyed the internet to see whether their anatomy and gaits resembled those of Furahan spidrids. As most of the robots out there seem to be hexapods, I made a quick hexapod version of my originally octapod spidrids (if you need information on spidrids, go to the land section of the Furaha site and select 'walking with...'). A mutation, if you will.

Mutated spidrid; copyright Gert van Dijk

And here it is. I cannot call it a spidrid any longer, as that name evoked spiders, and therefore eight legs. Suggestions are welcome. The beasty walks with the simplest possible gait: that is a double tripod gait, in which the six legs are divided into two groups of three. The three legs of a group move in unison, and the two groups are exactly out of phase. Provided that each leg touches the ground longer than it is off it, there will always be at least three lags on the ground (either that or six). This gait, together with sprawling legs, provides excellent stability. As discussed previously, this is useful for very small animals, soupy atmospheres or a very low walking velocity. It also doesn't require subtle neural control, making it suitable for today's rather dumb robots. It is also a bit boring, which is why my spidrids walk with different gaits, but that is another matter.

Click to enlarge; copyright Gert van Dijk

Next, a scheme to show how the joint anatomy works. Spidrids are very simple: there is a joint at the 'hip', in which the entire leg can rotate clockwise or anti-clockwise. The rotation axis is vertical, indicated by a shiny metal axis and a red arrow. All other joints are simple hinges allowing the segments of the leg to be stretched or bent, and the axes are horizontal, indicated by more shiny axes and blue arrows. Now that the basic spidrid anatomy and gait are clear, it is time to see whether the robot creators have evolved completely different approaches, or whether they evolved the same ideas.

The first video is of a hexapod robot from this YouTube source. As soon as you see it move you will see that its leg anatomy is exactly that of the spidrid: there is one vertical axis at the hip, and the leg itself only contains horizontal axes. The gait is simple as well, in that the legs move in two sets of three, just like the animation above. I like the clunking sound it makes, as if a whole battalion of Cybermen comes clunking down the street. It does one thing my spidrid animations do not (as yet): it changes gait, in the sense that it moves from a circular rotation to walking again (I could have programmed that, but that is a lot of work...).

Here is another one (source here), and this one has a more biological feel to it, in the sense that the movements seem smoother and less mechanical. It does have the same basic anatomy though. Its gaits seem more diverse.

Just to show that radial robots are not restricted to six legs, here is an eight-legged one (source here), more reminiscent of the original spidrids. With eight legs there are many ways to move the legs, and the risks of falling are diminished, as it is easier to spread weight-bearing evenly around the centre of gravity.

Click to enlarge; source here

Finally, just a look at this one suggest a radical departure from the norm. It has four legs, but that is not the point, as it still clearly has a radial anatomy. The legs do not seem to be attached in the usual fashion: where they touch the body the joint seems to be a simple hinge with a horizontal axis. In fact, all its joints seem to have horizontal axes. So how does it move its legs in more than one direction? How can it walk if all its legs can do is stretch and shorten? The answer lies in its design: this robot is fundamentally different. It is part of a project in which the robot has an internal representation of its body, so it can learn to move once more after its legs have been damaged. In short, it is a lot more intelligent than its dumb brethren. If you want interesting movements, always add a brain (an insect type of brain will do).

And this video shows how it moves: it tilts its body, and that takes the place of (anti)clockwise leg rotations. By varying the tilt of its body the reach of its legs becomes much more varied than with an immobile body. In fact, with the anatomy it has, body tilt is the only way forward (pun intended). What a clever design! I love it.

Does this mean that the 'usual' radial design is flawed? I think not. There are good reasons why this design was invented several times, for robots as well as spidrids: it is simple and allows good mobility. Now, if the robots develop more interesting and sophisticated gaits, we are in business: model spidrids in your own home; what more could you wish for?

Epona Reconnaissance Flight (Epona V)

2010-10-23T14:57:00.007+02:00

The Epona Project was, or perhaps is, probably the first serious attempt to build an fictional biosphere from scratch. There is still a website, definitely worth watching. Admittedly, the project has stopped in the sense that no new life forms have been developed for a long time, nor is that likely to happen. But the website is being added to, and I return to it from time to time. The last blog entry on Epona is to be found here, while another one that shows the same scene as is shown in the film below is right here. This time, I used Vue Infinite (version 7.5) to produce a film of almost one minute duration.

How does this work? Well, first of all, there were the life forms to consider. Steven Hanly had modelled them in the past, and it proved possible to port some of his models into the Vue environment. The 'uther' you see flying in the scene is entirely Stephen's doing. The plants could not be used directly, as present-day computer imagery requires more detail than was available when he first designed the models. They were therefore designed anew, using XFrog for the large leaves of the pagoda trees and for all small plants. The stems of the large pagoda tress were done in Vue Infinite. The trees were assembled in Vue, and Vue's 'ecosystem' feature was used to create a terrain with a stream running through it. Then just imagine that a 5-second fragment of film may need some 34 hours to render.

After that, a bit of sound was added, a process I have hardly any experience with. I hope the result is not too jarring.

Anyway, there we are: perhaps the film is about a robot drone taking a look on an Eponan archipelago, covered by a pagoda forest. There is a larger version on YouTube. The original film on my computer is much better; I wish I knew more about optimising quality while compressing a video...

These legs are made for walking (Legs II)

2010-10-08T17:44:00.014+02:00

In my last post I played with some concepts about leg design, mostly concerning whether it is better to have sprawling legs or ones that function as pillars. It turned out that there is no answer that is always correct: for large animals pillars help minimise energy expenditure in the form of muscle power, and for small animals sprawling legs provide protection against wind forces, something that gets more consequential the smaller you get. Perhaps wind is also one of the reasons why small arthropods are so good at gripping surfaces tightly: I had thought that that was mainly a neat feature to cling to vertical surfaces or even to land on a ceiling, but perhaps simply keeping put where you are if there is a strong wind weighs in too. What do insects do when there is a real gale out there? Does anyone know?

There are still enough problems to play with. I took the Disneius species that had just evolved last time and decided to take its legs one step further, i.e., I tried to simplify their design some more. The reasoning was that legs largely have to move in the body direction, rendering movements in other directions less important. The result is Disneius mechanicus:

Click to enlarge; copyright Gert van Dijk

And here it is. This has taken the idea to an ultimate form: the joints in its legs rotate purely in forwards and backwards directions. Note that this would not work in real life, as the animal would not be able to turn. In real life you would want to make the feet and at least one joint higher up more adaptable.

The legs are built in a zigzag way, like those of its predecessors. Last time I discussed that avoiding bending ‘moments’ becomes easier the nearer the joints are near the centre of gravity. Mind you, zigzagging legs in which the joints zigzag inside and outside are not necessarily worse than ones that do their zigzagging forwards and backwards. The usual explanation for the anatomy of mammal legs is that ‘vertical’ is better, but just suppose you take one of D. mechanicus’ legs and turn it by 90 degrees. If its foot was directly underneath the hip joint to start with, the rotation will not change that. The joint angles do not change either. All this leads me to conclude that ‘verticality’ in limbs depends more on having straight legs than on the direction the joints zigzag in. Legs that predominantly move forward and backwards have the advantage of allowing simpler joints, and simpler joints may allow less muscle strength to control their position: a good thing. I would expect large animals with highly evolved legs to adopt forwards and backwards bending as well. A bit boring, but that is what you get with universal laws of nature.

Luckily there are enough items left that might make alien animals more alien-looking. As you can see, the fore and aft legs of D. mechanicus are exactly alike. This is not what mammal legs look like. From a mechanical point of view fore and aft leg tend to have different effects, with aft legs providing more propulsive force than front ones. Is that also the reason why mammal knees point forwards and their elbows backwards? It seems as if, starting with a newt, its upper arms were rotated backwards and its thighs forwards to turn it into a mammal with fore-aft moving legs.

Click to enlarge

Here is a picture from this site that explains just that phenomenon. It explains why the bones in the forearm are crossed while those in the leg are not. But that is just one way to look at things. In the same newt-to-mammal trip, a third large movable segment was added to the newt's two. In the front leg the shoulder blade turned into a movable segment, and in the hind leg foot bones were recruited. If you look at the result from a functional point of view, the first large movable segment is the shoulder blade in the front limb and the thigh bone in the hind limb. Both point forwards, and from that the other segments zig backwards and then forwards. That is what D. mechanicus looks like! Based on this functional view, I feel that identical front and hind legs are theoretically quite possible. Prolonged specialisation for braking and weight carrying (front legs) and propulsion (hind legs) might change some aspects, but I see no need to ‘prescribe’ the typical mammal pattern as the only feasible one.

Click to enlarge; copyright Gert van Dijk

So here is a variant (the left one) in which the upper segments starts the zigzag by pointing backwards, not forwards, as in the righthand side one. Can this work? At present I see no reason why not. Perhaps I should do some animation studies to see if any big problems come up. But if there are none, an animal could have front legs that start with a zig and hind legs that start with a zag, or vice versa. They are in the background of the image above, but a closer look follows.

Click to enlarge; copyright Gert van Dijk

And here they are: we could make up interesting leg formulae, like ‘zigzig’for an animal in which both front and hind legs start with a forwards zig (and in which the other segments follow the lead of the first segment). ‘Zagzig’ denotes an animal with a front leg starting with a backwards zag while the hind leg starts forwards. You can think of what a ‘zigzagzig’ means for yourselves.

Click to enlarge; copyright Gert van Dijk

Just for fun here is a herd of the beasties. How many zigzags should there be? I do not know. If there is a proper foot, in which many segments touch the floor, I would expect all of them to bend backwards to promote ‘rolling’ over the ground. If just one segment touches the ground, as in hoofed mammals, I have no idea. But the majority of long segments will likely zigzag.

Click to enlarge; copyright Gert van Dijk

Here is an animal with more zigzags, along with an ancestor. The giraffomorph looks weak to me. There must be an optimum number of segments to achieve good manoeuvrability and/or good speed, but I do not dare speculate on that, or at least not now. I also do not know why the scapula in mammals is not connected by joints to the vertebral column, in contrast to the hind legs. Does it have to do with shock absorption versus propulsion? Perhaps those are good subjects for later posts.

Legs to stand on

2010-09-22T19:12:00.010+02:00

When I sketch a large alien animal, its legs tend to take on the shape of Earth legs with a life of their own. Depending on their general way of life, the animals' legs look like those of mammals, reptiles or amphibians. When the animals are insect-sized, the legs that take shape on the paper are thin and stick out sideways. Apparently the parts of my brain that are responsible for these patterns are so indoctrinated by life on Earth that it takes an effort not to produce them. I am not alone in this, as a glance at websites such as Speculative Evolution will reveal.

Click to enlarge; from 'Primeval'

The wish to 'alienate' the animals can easily result in trickery, such as inflating the arthropod design to the size of a large mammal, or to give the animal tentacles to walk on. The two images above are from the series 'Primeval', a British television series (I like it, by the way!). The heroes encounter some Silurian animals. As you probably know, there were some impressive arthropods around at the time, but they weren't impressive enough for the makers of this series. A pity, as there are enough ways to tell a good story without being silly. There are various reasons such animals could not be that big, and they could no more cling to the ceiling than you can. Effects of scaling are largely to blame, discussed earlier here and here.

But even if you do take physical constraints into consideration, there are thousands of intriguing questions to ask. For instance, if sprawling legs are a bad idea for large animals, why do small animals have them? Why do mammal legs folded in a zigzag manner, with successive bones pointing in opposite directions? Why shoulder blades? What is the optimal number of leg segments? This post presents some -rambling- thoughts on such questions.

Click to enlarge; copyright Gert van Dijk

Let's start with an animal with insect-like sprawling legs. It's not insect-sized though, but mammal-sized. There are four legs, but that is not the point. There are three segments to each leg, but that is not the point either. The joints are all ball and socket joints providing movement around three axes each; that is a bit much, but I will get back to that.

It does not look comfortable, does it? Neither would you if you had to walk around in a similar position: like doing push-ups all day. The poor beast (Disneius salamandris) will have to spend a lot of energy to keep its body from sagging to the ground. In other words, it takes energy to keep the joints in their current positions. To understand how you can minimise that force requires a bit of knowledge about levers, vectors and torques.

Click to enlarge; copyright Gert van Dijk

Here is a drawing of the body with just one leg. Let's pretend the body and parts of the leg are stuck together, so there is just one joint to consider (where blue and brown meet). Gravity pulls at the mass of the animal at its centre of gravity, with a force marked 'W' (for weight). How much 'turning power' does that result in at the joint? Easy: connect the joint and the centre of gravity with a line of distance d. Now, using vectors, draw the component of W that is at a right angle to line d; that force is what turns the joint (marked with a black arrow 'R'). The longer the arrow for R , the higher the force. How much turning power this exerts at the joint is obtained by multiplying d with F: the turning 'moment' or 'torque'.

Click to enlarge; copyright Gert van Dijk

To make that a bit more intuitive I overlaid a wrench on the graph. The wrench grips the joint, and the part where you would put your hand is at the centre of gravity. To use the wrench you would pull or push on it at a right angle to it, right? That would be the force 'R'. The harder you pull, the larger the torque will be. If you were to use a longer wrench with the same force, you would also get more torque. More force and longer handles; that is about all there is to it. Back to D. salamandris; it will have to exert an equally large torque of its own using muscle forces -not drawn- to stop the joint from moving.

Click to enlarge; copyright Gert van Dijk

Here is the same reasoning worked out for another joint. In all cases the torque, the product of multiplying d with R, calls for lots of muscle power. Avoiding all this energy expenditure calls for minimising the torque. You can make d smaller by getting the joints as close to the centre of gravity as you can. Minimising R also works, and to do that you should make the line d as vertically as possible: get the joints underneath the body. I think that this principle also explains why legs tend to bend in zigzag fashion: it keeps the joints more or less close together and minimises gravity-induced torque. So, poor D. salamandris does it all wrong.

Click to enlarge; copyright Gert van Dijk

But before we let D. Salamandris go extinct, let's have a look at what its sprawling stance means for the anatomy of the joints in its legs. Above you see one leg in a few positions, obtained by rotating it around the axis in the joint connecting it to the body. To get a movement suitable for walking, its foot should move in a straight line from front to aft (in reality the foot would stay put but the body would move forwards; seen from the body it is the foot that moves backwards). Getting the foot on the stripe only requires straitening some of the joints a bit. But ensuring that the foot always points forwards also requires that there is a way to rotate some of the bones around a longitudinal axis. If you start to think about this some more, you will find that having legs stick sideways requires rather complex joints; it may seem easy, but is not.

Click to enlarge; copyright Gert van Dijk

Here is an intermediary stage in standing on one's own legs: this animal has brought its feet in underneath its body, and its legs show a zigzag pattern, but mostly sideways (a final stage will appear in a future post). This does not solve all problems, as you may well ask why insect do walk with their legs sprawling to the sides. After all, if bringing the legs in is so advantageous, why do not all animals do so? There may be two answers to that. Sprawling and having bent legs is not advantageous if gravity is a big problem, as such positions require lots of muscle power. As discussed previously in my posts on scaling, such problems increase very quickly as animals get bigger. Make them smaller, and the added energy expenditure hardly counts any more in the overall budget. There is also an advantage for small animals to have sprawling legs: it helps them from being blown over by the wind.

Click to enlarge; copyright Gert van Dijk

Above is a similar drawing as previously, but now with a horizontal force acting on the animals: wind. Wind forces can cause the animal to topple over, and once again the component of wind force that does that is at a right angle to the line connecting the centre of gravity to the point of rotation: where the feet touch the ground. The animal with the lower centre of gravity and the more sprawling legs is better protected against wind forces: the force R is small and directed upwards, meaning the weight of the animal counteracts it. For the upright animal the story is different: R is directed sideways, is not counteracted by gravity, and the animal only needs to tilt a bit before the centre of gravity is no longer above the feet.

Once again, scaling plays a part: when you are very small, wind forces play a relatively larger role than at our human size. The same works when you supplant air with water: walking under water will be very difficult if the water is streaming at some velocity. So, vertical legs become more advantageous when animal mass increases, and the more so on planets with a strong gravity. Horizontal, sprawling legs are better when being blown over is an issue, and that is more likely to happen when animal mass is very low, when the atmosphere is very syrupy or the wind becomes stronger. Which legs are best when you are an animal on a very high gravity world with gale forces howling through its soupy atmosphere? Difficult to say; perhaps it should have vertical weight-bearing legs as well as lateral struts...

Whose alien plants are these ? - bis

2010-09-15T18:19:00.004+02:00

'Anonymous' gave the right answer yesterday, when I had already written the first draft of this post. The 'paintings' I showed last week were in reality photographs of glass works of art displayed in natural surroundings. The artist who made them is called Dale Chihuly, whose work I found by traversing the internet looking for alien plants. I rather like the plant shapes he produces: they are very organic looking, and displaying them among real plants provides a pleasing contrast. I thought that showing them in their original form might have made the riddle a bit too easy, which is why I turned them into 'paintings'. I did so with Corel Painter, by the way.

Click to enlarge

Above are the three images I had worked over, but now as I found them on Mr Chihuly's website, right here. There are two more I did not work over to give you a further taste of his work. If you wish to see more images of his plant-like creations, you will find many more of them under the column 'temporary' of the 'installations' page; just pick something from the right-hand column and have a look.

After this intermezzo I will be back with a post about legs, discussing things such as why splaying them works for very small animals but not for large ones, and why bones of large animals have a tendency to fold in zigzag fashion.

Alien plants III: whose plants are these?

2010-09-09T20:39:00.003+02:00

While the busiest part of the year for me usually lasts from the middle of August to the middle of July, the present period presents problematic peaks. In short: not enough time.

Therefore I will just continue the alien plants theme by showing a few images of otherworldly plants. So who made them? Do you know?

I warn you that I cheated: the images have been altered to prevent any immediate recognition. I will post the answer in a next post, along with the unaltered images.

Click to enlarge

Adding oddity (alien plants II)

2010-08-28T18:02:00.006+02:00

Click to enlarge

I don't write often on alien plants, for a simple reason: there seem to be few of them. I wrote about the -real!- plant life on the island Socotra once, shown you Furahan swamps and showed a few images from the British comic strip Dan Dare. My main post on alien plants was devoted to a computer-generated video. The firm that made it produced another one, as I learned from a site called dexigner.com. The images shown here and the video are taken from that site (the video quality on the site is very good). In fact, there I learned that the previous one was called 'Sixes Last'; there are so many copies of it on the Internet that it is not hard to find it, but it is hard to trace its origin. The 'new' one dates from 2006 and is a commercial for an alcoholic drink. I have nothing against that; in fact, C2H5OH plays quite a role in Furahan biochemistry. As 'advertisement' is not exactly a synonym for 'accuracy', do not expect much in the way of plausibility. Then again, the film does not try to be accurate, just intriguing and humorous. It succeeds well, I think. The computer-generated bits seem to be added to real footage, which may explain why the images look very real.

Click to enlarge

The second reason to show it is to discuss the problem of how to design odd plants. I have this worrying idea that the basic plant design may not allow much creative freedom, at least not if the definition of plant is not stretched too much. The main ingredients of the definition may be photosynthesis and being sessile, with some -arbitrary- limits in that the plants in question are multicellular and that they are land plants. Photosynthesis needs light, and the best way to get much light is with a large area, i.e. thin shapes. Needles are good but planes are better. Basically a blanket-like shape with roots to pick up minerals and water is all you need. But if the blanket gets too large it may be torn by the wind, and an easy way to avoid that is to distribute wind stress over many small leaves. Growing towards the light avoids being in the shadow of other plants. Branching systems and leaves seem unavoidable, and any alien plant with those will look like an Earth plant.

What can be done is to alter the relative sizes of plants: thick stems, enormous leaves, etc. and giving them odd colours. But there are usually reasons for these proportions as well as for colours, so there is no total freedom here. The simplest way to add oddity may be to add elements of animals: give the plants eyes or mouths. That is what happened in the earlier video as well as in the present one. Eyes are there to tell an organism about its environment: where is the prey, where is the predator, are there good-looking potential mates around, etc. Acquiring information is only useful if you can act on it, and the main limitation here may be the sessile lifestyle. Sessile life forms can certainly be interesting; there are quite a few sessile predators: think of anemones. But there may be a limit on how well developed their sense organs and brains can become. Why have fine eyes and precise grasping arms when your reach remains frustratingly limited? Wouldn't an animal that can do the same things but that can move around be vastly more fit in the evolutionary sense? You may counter that by saying that it may be enough to outperform the dumb and blind types of sessile organisms. In evolutionary biology traits always seem to cost something. The price to pay may be a metabolic one: eyes, muscles and particularly brains are very expensive in terms of energy.

In that sense, high class eyes are jetset organs, reserved for high flyers only. So the puzzle remains how to increase the oddity of alien plants...