To cernuate or not to cernuate... (cernuation III)

It would appear that my previous explanation of cernuation left something to be desired, so I will try again. When I coined the word, I was thinking about a mode of locomotion invented by the people responsible for 'The Future is Wild' (TFIW). The squibbons, descendants of cephalopods, have taken to the trees and swing from branch to branch from their tentacles. That could be just what a tentacle might be good at, as it mostly involves tensile forces; tentacles are not well fit to withstand compressive forces needed for walking.

Brachiation is what comes to mind when gibbons or monkeys swing from branch to branch: they hang from one arm while the other swings to grab another branch. While they do so the body stays largely upright, meaning the head is always above the feet.

The way squibbons do this, cernuation, has similarities: the animal swings suspended from one or more arms while other arms move forward to grab a new branch. But the movement is like an inverted somersault, so, while one swing sees the head upwards, the next has it downwards. I presented a fragment of 'TFIW' showing a squibbon moving that way, but the lighting was not very even so the movement may not have been well visible. This post rectifies that.

Click to enlarge; copyright Gert van Dijk

Above you see a rough model of a cernuator. It is only a simple ZBrush model, not meant as a proper animal (I hope my ZBrush friends will forgive me). The animal has very long eye stalks, long arms and long legs, and the head is kept downwards so the eyes stay near the centre of the body; the body is even bent to make room. Having the eyes near the centre was borrowed from the squibbon; this particular concept is stressed in the book 'TFIW'. The idea is probably that this eye position minimises the vertical distance the eyes travel over during cernuation. We'll get back to that.

Click to enlarge; copyright Gert van Dijk

This image shows part of the movement cycle, starting when the body hangs vertically from the arms, and ending where the animal can grasp another branch with its feet.

Click to enlarge; copyright Gert van Dijk

The next diagram starts at the same stage, and ends at the point where the hands are ready to grasp a branch. Note that the animal is upside down during this part of the movement, and moves with its back towards the direction of swing.

Click to enlarge; copyright Gert van Dijk

And finally the animal swings from its hands right up to the point where the cycle began. Notice that the body is now right side up again, and the back faces, well, backwards. That's cernuation.

As I wrote before, I admire the ingenuity that went into its design. The more I think about it though, the more I start doubting how well it would work. There is no mechanical problem at all in swinging like this. Instead, the problem is one of motor control and of visual perception. It is amazing that animals like gibbons actually manage to travel through woods at high speeds. Just imagine how much more difficult their task would be if their image of the world not just zoomed forwards as well as bobbing up and down, as it does in brachiation, but also rotated constantly as it must in cernuation. Have a look at the animal's head above: it is actually turned upside down at one point. How do cernuating animals manage to pick out the next branch?

Click to enlarge; copyright Gert van Dijk

That must have been the reason why the squibbon's designers situated its eyes near the centre of mass. The picture above shows all stages in the movement, with a black line indicating the position of the eyes. Compare that to the position of the feet or the hands (blue line), and you will see that the centre of the body moves less vertically than any part far away from the centre. You may now also understand why the squibbon's eyes stick out sideways: if not, it would not be able to look forwards at times because its body would be in the way!

Click to enlarge; copyright Gert van Dijk

While this eye position minimises vertical displacement, it does nothing to solve the problem of the eye rotating, and with it the animal's view of the world. Perhaps that can be rectified. Let's suppose the head can be rotated by about 180 degrees. Have a look at animal A shown here. Hanging from its hands like this it will view the world as being the right side up. If it were to change the position of its head as in B, it would see the world upside down, right? That is not at all useful, unless of course the body itself would be upside down. Obvioulsy that is the case while cernuating, so if we take animal B, freeze it and rotate it, head and all, you get animal C. The trick would be for the animal to rotate its head from one position to the other quickly when the point of contact changes. During the swing, the animal could then always keep the head in the same vertical position so it could see what it is doing! I do not know whether squibbons were supposed to this by rotation of the eye stalks, but why not...

Mind you, I think brachiation is by far the easier solution, and I do no intend to fill Furahan forests with screeching cernuators. Still, it is interesting to think about, isn't it?

This is probably the point where the rift between those who say 'yes' and the vast majority of mankind is revealed...

Brachiation versus cernuation, as well as mono- and tribrachial brachiation

I have tried to make the title of this post as obtuse as I could; I hope everyone appreciates that...

In my recent post on the marblebill, a Furahan brachiating predator, I discussed several restrictions that a brachiating lifestyle puts on an animal's body plan. Among others, those were a need for other limbs beside the swinging ones, so the animals would also be able to walk as well as climb vertical surfaces. There is of course no need to completely separate such purposes among limbs. After all, gibbons use their arms for climbing and walking as well.

I also wrote that I knew of only one other brachiating type of animal in speculative evolution, and that this was the squibbon in 'The Future is Wild'. It turns out that that statement was wrong on at least two counts. Firstly, in Dougal Dixon's 'After Man' there is a striger, a tree dwelling feline carnivore. Although its description does not stipulate brachiation, the accompanying picture certainly suggests it. There are bound to be other brachiators too somewhere in the growing field of speculative evolution. Secondly, the squibbon does not brachiate at all! It somersaults, meaning its body is upside-down at some stages in its locomotion, which is a fundamental difference with brachiation, in which the body stays upright. I should have checked that before I wrote it.

Clip from 'The Future is Wild' DVD

To illustrate the difference I have cut a short clip from 'The Future is wild' to show the squibbon's way of propulsion through the trees (easily available through Amazon etc). I know of no Earth animal that does this, so this is really a very ingenious design. Often when you try to think of a novel animal locomotion, evolution has been there and done it already. It is a pity that the designers did not give this locomotion mode a nice name. I now propose 'cernuation', derived from the verb cernuare, meaning to 'fall headfirst / dive / turn a somersault'. Cernuation does pose a problem than brachiation does not: the visual field rotates 360 degrees in each jump, which must make the job of working out where to jump at high speeds even more difficult than it already is. The placement of the squibbon's eyes near the horizontal axis around which it cernuates proves that a lot of thought has gone into this animal. Being on the axis the visual field will still rotate 360 degrees with each movement, but will not shift as much as when it would be somewhere else (there may be room for creativity here though).

The remainder of this post will deal with the number of limbs involved in brachiation. The marblebill uses just two arms for brachiation, just like gibbons and other brachiating primates. This being a blog about speculative biology, the question rises whether it can be done with other numbers of arms.

How about just one? Theoretically this is possible: the animal has to leap from one handhold to the next. There would be no way to go slowly though, as you can with two arms. Slow-moving brachiators can afford to let one arm go while the other has a firm grip. In effect, one-armed brachiation is very much the same as hopping on one leg: each hop is a jump and requires lots of energy. It would be dangerous as well.

Two arms has been dealt with, so three is next. Actually, there are three-limbed brachiators on Earth: there are brachiating monkeys using their tail as well as their hands. When I discussed walking with an odd number of limbs, I could not find any animal that did so with three legs. Tripod walking poses the problem of phase: do two legs move together while the third moves on its own, or is the cycle divided in three equal parts? In the monkey case, the starting point is bilateral symmetry: two limbs are paired and the tail is not, which suggests that an equal division of the cycle is not feasible. The other possible solution is not the case either: that would be that the two arms swing together while the tail holds a branch and vice versa. So how does it work? Essentially the monkeys alternate their arms in the usual brachiating way. The tail helps along by being placed in time with the hand, and right next to it, in fact. Moving the tail in this way may act as a safety mechanism, but has an effect on body sway as well.

Click to enlarge;

Turnquist et al; Pendular motion in the brachiation of captive Lagothrix and Ateles.

Am J Primatol 1999; 48: 263-281

The image above requires some study. If the tail is placed next to the hand, does it do so for both hands? That is indeed possible, and the tail then moves twice as often as each hand does. The authors of the paper describe the movement as 'choppy'. I suppose that this may be only known locomotion in which one limb moves at twice the frequency as other limbs do. I know of one speculative animal that does this, but was not aware of anything of the sort occurring on Earth! This is not the only solution though: some monkeys use their tail in the same frequency as their hands, to the effect that the tail only helps one hand, either the left or the right one. Odd, isn't it?

Is brachiation with more arms possible? Theoretically you could do it with four arms, and the pattern then becomes an upside-down tetrapod gait. Nothing new there.

Can you brachiate with radial symmetry? Yes; an intriguing way would be to let each successive arm take the weight. Envisage a spoked wheel and roll it: the successive spokes point to the ground one after another. Of course, this causes the body the rotate once more, and gain the body's axis of rotation is horizontal, at right angles to the direction of movement, so this is cernuation once more.

There are no cernuators on Furaha, or at least not yet. I do not think that spidrid anatomy lends itself well to moving into the trees. One or two species sometimes roll downhill on their sides to make a getaway, but that is as close as they get. I wonder about other places...

Alternate Future Evolution in Japan

Satoshi Kawasaki is a Japanese illustrator, author, or both. Normally I try to get the facts correct, but in this case I am forced to rely on Google's translation services. While these allow us all to sample texts that would otherwise remain closed, the results are not necessarily reliable. For those who do not now how to operate the Google translation service, simply go the main Google page, and there should be something called 'language aids' or similar just to the right of the search window. Clicking on it will allow you to paste in text, or to translate an entire web page. To see how well or poorly it works, have it translate a paragraph in your native language into Japanese, and paste the result in to translate it back again.

Following this link will bring you to an Amazon page showing a book of extinct animals. I think it is a safe guess that most people interested in speculative biology will also like palaeontology. If so, the cover of this book should convince you that Mr. Kawasaki knows his business, and seems to prefer the bizarre. He does not shy away from speculative biology either, and in his case that concerns life in the future on Earth. He has a very nice website showing life on Earth in various geological ages, starting at the Cambrium. Clicking on an epoch shows a world map for that age, and selecting a continent or sea opens a page with its inhabitants. From the Cambrium on each major era has its own map. There are four such pages for the future, resulting in pages for 5, 50, 100 and 200 million years in the future. But before you zoom off to look there, stop at the other ages as well, because here and there you will find animals indicated with an outline and a question mark, and these are quite interesting.

Click to enlarge; copyright Satoshi Kawasaki

In the present era, I found this intriguing dog with a human face living in Japan and China. The text says that the animal is not suffering at all, but that this is its normal face; at least I think that is what it says. The garbled translation suggests that the original text might be quite funny, but that is something I can only guess at. At any rate, images such as this one show that Mr. Kawasaki has a somewhat surrealistic sense of humour, which I rather like. If you do not, be warned, because similar themes will keep cropping up. If you take speculative biology as a completely serious business, do not bother visiting his site. Of course, taking anything entitled 'speculative biology' completely serious is a bit surrealistic by itself.

I will not delve into all the animals, nor discuss in any detail how life evolves in the future. I rather liked the way how chameleons leave the trees and evolve into a range of large terrestrial animals, looking a bit like present-day mammals as well as like dinosaurs. What I also liked was that intelligent beings seem to evolve here and there, only to vanish without a trace.

Instead I will focus on the world of 200 millions years into the future, and on one theme only: land-living cephalopods! Yes, there are land-living octopus and squid here. Dougal Dixon was probably the first to shoo cephalopods onto dry land in his book 'Life after Man'. The theme was worked out in more detail in 'The Future is Wild'. I think there are some significant problems with this concept. One is that the cephalopod body structure simply does not provide a good starting point for an animal that needs to withstand gravity. Tentacles in particular are an extremely bad starting point. In earlier entries (last one here) I explained my reasons for thinking so. In short, you can walk on tentacles, but once evolution has increased their efficiency, they are no longer tentacles, but will have become legs. The second reason to think that cephalopods will have a difficult time making it on land is that they are not the first to go there, so they will have to compete with animals with fully developed legs. In 'The Future is Wild' swamps were provided for the purpose, but the other animals were not whisked away to support the cephalopods. Perhaps an isolated island, where there are no land animals at all, might do the trick. Even then you have to hope that birds won't bother the new-fangled land-squids too much. Mr Kawasaki's terrestrial cephalopods do not seem to care one bit about such sombre estimates of their likelihood, but look quite alive. Let's have a closer look.

Click to enlarge; copyright Satoshi Kawasaki

This one is entitled a 'Purototerasukuido', and is described as a primitive 'Terasukuido'. Let me guess: 'sukuido' might be a Japanese transliteration of the English word 'squid', and 'terasukuido' might be 'terrestrial squid'. 'Puroto' could be 'proto-', so this might be a proto-land-squid'. The animal looks like it is lifted bodily out of 'The Future is Wild', so it seems like Mr Kawasaki is playing another joke. It is describe as a living fossil, and the statement that high fertility balances high mortality shows that Mr Kawasaki also thinks that such an animal needs all the help it can get to stay alive.

Click to enlarge; copyright Satoshi Kawasaki

Next: a goby squid. The text says 'Second is to leap out of the crab', which may mean that it is an ambush predator, waiting for a crab to emerge. It has six walking legs and two prehensile arms, which makes sense, I think. It somehow manages to look very attentive, indeed like a little goby fish.

Click to enlarge; copyright Satoshi Kawasaki

This is a 'Sleipnir', named after Odin's eight-legged horse. The first animal shown above is a functional hexapod, using two arms for predatory purposes. Perhaps this is another example of centaurism, but that is debatable. The Sleipnir lives in herds and is well-protected by scales. Its length is given as 200-250 cm, so it is quite large. The legs might still be tentacles, but they might just as easily have bones in them; perhaps this is an example of a tentacle turned into a leg.

Click to enlarge; copyright Satoshi Kawasaki

An African predator? Yes, the 'chitopasu' is a sprinter; is there a cheetah in that name? In this case, the text clearly states that there is no skeleton in its legs. What a pity. Note that the illustration is apparently not by Mr Kawasaki but by 'UME'.

Click to enlarge; copyright Satoshi Kawasaki

The Zeburasukuido must be prey, and it is (I guess its name means 'zebra squid'). Note that the mouth is underneath the animal, while he eyes are on top, just like its ancestors. I do think that the eyes should probably be smaller, as eyes do not generally scale in the same way as body size. Having such large eyes makes it look much smaller than it is supposed to be. Count its legs: there are ten this time! All this leg variability suggest that land squids are not a monophyletic group; that means that the species shown here are not descended from a single species. Instead, their resemblance suggests that various groups of cephalopods all made it onto land, bringing their different body plans with them. Not impossible, but what would drive such a tendency?

Click to enlarge; copyright Satoshi Kawasaki

Finally, a brachiator (that's an animal swinging from its arms). It looks agile, as it should be. Its legs are attached to the underside of the body. If these animals indeed hang from branches much of the time, instead of sitting on them, the attachments of their legs might wander to the top of the body, making life a little easier mechanically.

I really like the sense of humour that permeates these creatures. It would be nice to have Mr Kawasaki tell us a bit more about his creations, and perhaps he will respond. Until then, have fun with his website and his creations.

The Future is Wild... and it is Manga!

My plans to write posts less frequently are thwarted (I've always wanted to use that word) by being spoilt for choice. Greenworld should be good for two posts, Avatar is nice, particularly the odd choices the designers made when it came to locomotion, some bandes dessinées deserve attention, etc. I decided to continue with the Japanese theme a bit. I guess that readers who really like speculative biology will have come into contact with 'The Future is Wild' (TFIW); after all, there was a television series, there are books, there is theme park in France and there are websites. In fact, a commenter on the blog once expressed irritation with an overdose of 'The Future is Wild'. I sympathise with that, as I have felt the same from time to time. After a certain point you know the images and the animals, and repeated exposure to the same images or clips no longer excites the viewer. Apparently a new TV series is in the making as well as a cinema version, so there should be lots of new images. This post is about the 'old' TFIW animals. In Japan they have turned it into a manga, or comic book, published by Futabasha. In several European countries, France foremost, comic books are regarded as an art form: the neuvième art (ninth art). Like films, their styles differ appreciably between countries, which adds to their enjoyment: 'bandes dessinées', 'comics' and manga are not the same at all. My knowledge of mangas is rather poor; it seems that almost anything can be turned into a manga, and TFIW was no exception.

Click to enlarge; copyright Takaaki Ogawa

This is its front cover. As you can see it mentions Dougal Dixon, John Adams and Takaaki Ogawa, who I gather is the artist, i.e., the mangaka. I picked up a copy through Ebay, but if you want to you can easily order it through Amazon in Japan, which has English pages. You may well wonder how you turn a documentary about animals into a manga. Easy: just add a story. That is what this book does. In fact, quite a few wildlife documentaries do exactly the same. There are about 250 pages, containing 8 stories as well as a glossary, and introduction and some other bits and ends. There is some anthropomorphism, in which animals' emotions are shown on their faces in a way recognisable to humans (by the way, the image language the Japanese use seems to differ a bit from European usage, but not so much that the message is lost -I think!-). But adding anthropomorphism is again not too dissimilar from what happens in some nature documentaries (the best do not). The various TFIW stories have different themes. I have picked out images from two stories. One story deals with an individual adult toraton (I will assume you know your TFIW, and if not, the internet will provide). A young toraton disturbs a swampus, which bites it on the neck, and the startled youngster swings its head out of the way and accidentally pokes out one of the adult's eyes. That is the setting for the following page.

Click to enlarge; copyright Takaaki Ogawa

Mind you, manga are typically printed on somewhat grayish paper and aren't that big, meaning that the contrast of these scans is much better than what you see on the printed page. The images are quite large, so you can have a good look (but downloading might take time!). You can work out the story for yourselves: the young animal dies, and the adult has lost an eye (it later dies as well). Did I mention that you should learn to read right frames before left frames, in the reverse order you are used to? I might be wrong about the story line, not being able to read the text in Japanese. If I am, I hope that any Japanese readers will correct me. The reason to choose this picture was not primarily the sad story of one toraton's death; instead, there is an interesting scene in the foreground of the last frame. Here is a detail:

Click to enlarge; copyright Takaaki Ogawa

Stomatopods, my favourite! Mantis shrimps, and on land too! Were they in the TFIW documentary? I think not, otherwise I would probably have remembered. After all, they were the inspiration for Furahan hexapod predators, exhibiting centaurism. These mantis shrimps seem to be devouring a frog together, and as far as I know current mantis shrimps are firecely territorial. So these are social terrestrial mantis shrimps; impressive. I wonder what would hapen if squid and mantis shrimp somehow would make it onto dry land. Personally, I doubt terrestrial squid would have stood much of a chance: the squid have to develop a feasible mode of walking, and the mantis shrimp have that already. I wonder whether the mangaka added the stomatopods for his own amusement? The remaining images are of the squibbon / megasquid story. I discussed the megasquid before, and decided that I did not think walking on tentacles was at all likely, and certainly not for something as large as a megasquid. For squibbons the story might be a bit different, but still they seem unlikely. But never mind that now.

Click to enlarge; copyright Takaaki Ogawa

This page I like for its graphical qualities. I can only guess that the story alludes to the squibbons possible intelligence; are they pondering the age of Earth or the size of the Universe?

Click to enlarge; copyright Takaaki Ogawa

Thirteen pages later there is this lone squibbon. being social animals, a lone squibbon is probably a sad squibbon.

Click to enlarge; copyright Takaaki Ogawa

The next page seems to show a happy ending: other squibbons offer bioluminescent thingies (fungi?). Looking at TFIW in this way may take some getting used to, but I rather like it. Computer generated images still tend to look a bit stiff or awkward, and as long as they do so, I prefer drawings or paintings. Paintings are often much livelier and they also appeal to the imagination more than CGI renderings. This manga is lively, and, provided you increase the contrast, the graphic qualities of some pages and panels is good. I found that it does not matter that much that I cannot understand Japanese. I am obviously missing some information, but I certainly cannot complain about a lack of a sense of wonder: there is quite a bit of that.

Future evolution south of Brussels

So they have a Propellonectes on display in Brussels, but on the websites of the artists who designed it is a Calcitriornis.

If the previous sentence makes no sense to you whatsoever, please read the entry dealing with this subject first. In effect we are talking about an exposition in Brussels that includes some future animals. I had been using Google to find out more, but need not have bothered, as the material I was looking for is available on the websites of Marc Boulay and Sylvia Lorrain. The three sites contain largely the same material but are not identical, so it pays to visit all three.

Click to enlarge
© Marc Boulay / Sylvia Lorrain - ADAGP Paris 2000-2009
© Jean-Sébastien Steyer - CNRS 2000-2009

I will just show you some images of 'Benthogyrinus' to make you curious. What you see here is a poster-like image with some explanatory text. This states that we are looking at the very last amphibians, descended from the frog genus Xenopus. The species now is an ocean dweller, filling the niche whale sharks once lived in. The animals have developed a salt-excreting gland allowing them to cope with their salty environment. They do not actually look much like frogs, but there is a good reason for that. They are neotenous, meaning that they become sexually mature while formally still being in a larval stage. In effect, they are giant tadpoles. Very giant tadpoles, as they measure up to 20 meters. The males are two or there times smaller than the females and are shaped differently. The next two images illustrate all this nicely.

Click to enlarge
© Marc Boulay / Sylvia Lorrain - ADAGP Paris 2000-2009
© Jean-Sébastien Steyer - CNRS 2000-2009

Click to enlarge
© Marc Boulay / Sylvia Lorrain - ADAGP Paris 2000-2009
© Jean-Sébastien Steyer - CNRS 2000-2009

By the way, if you see a heading 'demos' on their websites, do click on it, as it will lead you to some 'exe' files that provide a slide show with music showcasing their work. Those are definitely worth taking a look.

Nice as all this is, it does not explain why Calcitriornis is the same as Propellonectes. Calcitriornis predates Propellonectes, as is evident from the copyright dates on the images. The answer is given in one of the interviews, and if you want to read it, there is a link on Boulay's site. Here is part one, en here is part two if you need a shortcut. The interview dates from 2006 and mentions a plan for a park on evolution, and that was to contain a section called 'Demain; les animaux du futur' ('tomorrow; the animals of the future'). The same protagonists were involved that we encountered in the Brussels expo: Steyer, Boulay and Lorrain. I do not know whether Dixon was formally involved, but the text makes it clear that they were in contact. That probably explains the traces of his 'Zoology of the future'. Unfortunately for those of us who like such things, nothing came of the plans.

That is sad, but at least it explains the history behind the Brussels' beasties: they were part of an earlier attempt to create a new future. I wonder whether we will hear and see more of the plans from this trio. I hope so.

Oh yes: Jean-Sébastien Steyer has written a book on life before dinosaurs; compared to the dinosaur era that is a time that deserves more attention, and the book looks very good. It is in French, and here is a link.

Just an aside on 'the future is wild'

I suppose that people with an interest in 'fictional biology' are among the readers of this blog. I do not think I will have to introduce the TV-series 'The future is wild' to them, so I won't. However, something that may have escaped attention is a theme park in France called futuroscope. It has the animals of 'The future is wild' parading in front of you, in what is 'enhanced reality': you look through goggles at a stage set with rocks etc., or so I gather. The image of the animals is then cleverly added to the image you personally see, thereby allowing you not just a personal vision of the scene, but to interact with the animals. They also have a bit of software you can use at home to try this out, if you have a webcam.

The techology is very intriguing. The site appears to be in French only, but if you wish to see what it looks like to have a squibbon jump on your hand, select 'le blog' and watch the videos. Intriguing, but odd.