Saturday, 24 November 2012

Thomastapir’s Xenohox Gazelle

Readers who have followed my Furaha work and this blog will know that I take a strong interest in biomechanics and locomotion, resulting in studies and animations of concepts such as six-legged gallops, radial walks and tetropter flight. There is of course another drive at work, and that is the wish to create something new, something truly alien. Given the immense diversity of life of Earth I used to feel that there probably was not that much that blind evolution had not yet stumbled upon, but later I felt that the limited number of basic animal shapes on Earth does in fact pose limits on the shapes we see, varied as they are. Hence forms such as spidrids and tetropters that I consider among my most original animal schemes. But at heart I am a bit conservative, which is why I hesitate to depart from known and tested body schemes.

Luckily, not everyone lets himself be restrained in this way, and that is why I would like to draw your attention to the work of thomastapir, whose work can be seen at deviantART. Like me, he likes locomotion and biomechanics, and he has produced some truly original creatures. I will only focus on one of his aliens here, but his dinosaurs and mythical beasts are well worth an visit. I will very likely revisit his page one day to discuss the 'Moebius inside out animal'.

Click to enlarge; copyright thomastapir

Xenohox Triphidian
I should perhaps jump right in with the Xenohox gazelle, as starting there will give you the full sense of wonder, but it would need a lot of explaining at once. Starting with this forerunner, here in its original place, has the advantage that its shape can be taken in fairly easily. Now this shape is new. One way to look at body shapes is to smooth the surface of animals until the shape cannot be reduced further, revealing its topology. Limbs, as simple protrusions, disappear, and our own vertebrate shape reduces to a blob with a hole through it, i.e. a torus: our digestive tract forms the hole. Jellyfish have no such hole, and can be reduced to a blob, or probably even a sheet. Thomastapir's animal represents three half tori mashed together.

Click to enlarge; copyright Gert van Dijk
That is what you see above: the blob on the left with a hole through it represents humans and our Earth kin us reduced to our basic topology, whereas the more complex structure on the right is the triphidian. The points where the three half tori join would be natural spots to place the machinery of an animal, meaning its digestive, respiratory, cleaning and neural tracts, along with other odds and ends that need not be universal, such as spleens. The legend on the deviantART page does state that the 'bodies' indeed house the organs. One is called the head and the other the body, which is almost a pity: departing the beaten track should perhaps be accompanied by more original anatomical names as well.

Click to enlarge; copyright thomastapir

Xenohox Gazelle    
The animal above, the 'Xenohox Gazelle', has the same topology as the triphidian. To develop it, we can pull at the surface to produce extrusions, in the same way we can pull at a single torus to sculpt a human or a millipede. The result of this sculpting are three strong limbs. 

You will probably need time to work out how this animal is built, and understanding how it moves will take more study. Thomastapir's remarks on his deviantART page explain how it works. He has chosen to keep the triradial anatomy fully intact. Others -well, me at any rate, see here and here- might have decided to let two of the half tori develop into weight-bearing structures, freeing the other one for other uses such as manipulation. Thomas kept all three as equally functional locomotor limbs, which inevitably leads to the conclusion that the animal must turn along its body axis to bring each limb towards the floor in turn. That is very interesting but also very complex. You will need a good ability to visualise movement in your mind's eye to understand it. This is the task: the animal is running across your imaginary field of vision, its body spinning like a screw as it does so. Each leg rotates along with the body, and when it is pointed downward, it also moves backwards pushing at the ground. When it moves up again it also moves forward. If you manage to visualise that, add the two other legs, of course with the proper phase difference. Got it?

If you did not, never mind, as I prepared an animation to help you see how it works. I am fairly pleased how it turned out, although it seems to move more ponderously than the name 'gazelle' suggests. Perhaps I stumbled along the analogue of a heavy eland antelope instead of a slightly built gazelle. 

I do see one problem with this way of movement, and that is that it adds complexity to sensing the world around you. The eyes turn with the animal, so the visual field continually turns around as well. That cannot help vision one bit. This is very similar to the problem I encountered in 'cernuation'. There was a solution though: the head would turn against the movement keeping the eyes still (of course, after one turn the head would have to snap back to allow a new counter turn). When I mentioned the vision problem to thomastapir he answered the following:  

"On the complication of vision due to rapid rotation about the long axis--it could be a matter of, let's say it has three eyes, that each eye takes a sort of "snapshot" at specific point in its motion cycle--say, when the given eye reaches the top of its rotation.  So then a composite or gestalt image is built up sequentially from those single snapshot images, almost like a flip book or film strip.  The rate of rotation is rapid enough that it should create a fairly smooth, uninterrupted stream of visual information. And certainly it could keep one or more eyes continuously open when it's motionless or walking slowly." 

That would probably work, but is not ideal either, as visual information would be lost some of the time.

Anyway, above is another animation with added drama. Nice, isn't it? The topic of how such animals stand still or walk slowly also came up in our conversation, and it appears there are several solutions for this. Would evolution leave the animal this way, or would it evolve towards a simpler 'same side up' form? Would its particular set of hox analogue genes even allow such an evolution? I do not know, nor do I care much, while enjoying the creativity of the Xenohox gazelle and its mode of locomotion. 


Anonymous said...

Where can I get an encyclopedia of Furahan life online when I'm in the UK?

Christopher Phoenix said...

Wow- that Xenohox Gazelle is weird, weird and way cool!! The Xenohox Gazelle's radically different body topology is quite interesting, as its unique method of movement.

In regards to the increased complexity of the Xenohox's vision, I can't help but think we may be applying our own human biases where they may not apply. Our senses are built to work well with our body, so when we think about what it might be like to be a Xenohox Gazelle, we imagine being spun around. Naturally, our vision and sense of balance would be totally thrown of kilter by such an experience. But, if the Xenohox Gazelle actually existed, doubtlessly its own arrangement of eyes and sense of balance would fit in with its own body plan, so it would not experience the disorientation we imagine in must.

That said, spinning around constantly does complicate sensing the environment, and it isn't clear to me how this would walk or trot slowly. Nor is it made clear how it eats- but maybe that will be made clear in later illustrations. The Xenohox Gazelle is so wonderfully alien, I am inclined to give it the benefit of the doubt. It would look wonderful galloping away from the landing site of a mysterious starship...

What's hard about this speculative biology stuff is that it is hard to come up with anything fun and alien without also coming up with something someone regards as "unrealistic". Ultimately, we are all confined in our experience to only ONE planet out of all the countless planets that exist throughout the visible universe, and until we build starships we won't see many more. So, either we come up with analogues of Earth species, or we come up with something different that we think is unlikely because no analogue has arisen on Earth (ballonts, tetratopters, Xenohox gazelle, etc.). Heck, we probably wouldn't believe in flying squids if they were the product of a SF artist's imagination rather than reality (Two methods of propulsion? Wasteful and unrealistic!!), as you mentioned in an earlier post. Just sticking extra legs on a horse is not "original" nor exciting, so I prefer the outlandish aliens- as long as they don't badly violate the laws of physics or chemistry, that is!! :-)

Unknown said...

You know, I often find it amusing that within the speculation community we can be so picky about what we like and do not like in terms of creature design! However, you've really hit the nail on the head in defining what it is that makes great alien design: the attempt to make bodyforms that are truly alien!

Great article!

Sigmund Nastrazzurro said...

Anonymous, are you the same person who asked the same question but following an older post. Well, I answered it there...
At any rate, there is no real book you can actually order (yet).

Christopher: there is indeed a degree to which the brain can evolve to cope with fast-moving images, but there must be limits to that, provided the basic elements such as retinal cells and neural networks are the same. Of course, what those limits are is anyone's guess. The thing is the movement really requires good vision, and to evolve that a good starting point would probably be slowly revolving creatures. That means the 'slow walk' has to be solved first.
S I am a bit worried about the vision problem, but not enough to let that stand in the way of enjoying thomastapir's creativity.

Ben: there is indeed a very tricky line between 'I like it so much I will ignore the problems' and 'one part is so bad that I must reject the whole'. For some reason we dislike opinions in the middle of that judgement process I must think about that some more.

Evan Black said...

I've always enjoyed thomastapir's work, and I'm glad to see you give it the attention of your expert eye. I'm also excited to one day see what you have to say about the moebius fish. It's a bauplan that I've occasionally played with in animation so as to more fully understand its locomotion.

One thought that comes to mind with the xenohox gazelle is the matter of torsion. You've done a wonderful job of demonstrating the creature's locomotion in your animations, but I wonder how the biomechanics might deal with a spinning body that wants to change directions. My initial impression is that, due to the creature's rotation, one direction may be easier to turn than the other, but could this have any noteworthy implications? For example, could predators depend on the fact that prey will tend to turn the same way when evading pursuit? Could there be 'lefties' as well as 'righties," exhibiting a large scale chirality, or could a single individual decide to rotate in the opposite direction? What other benefits/disadvantages might this twisting gait offer, and has thomastapir addressed any of these issues?

Ronan said...

The triphidian beasties are very interesting, but I don't know how comfortable I am with those big, swooping loops. I can't think of a single beastie on Earth that has an external looping structure, and considering that there are plenty of critters with INTERNAL loops, I rather suspect that there's a sound evolutionary reason for that (loops would snag easily on protruding bits of one's surroundings, if they get torn there's no way to repair them, etc.) I can also see a problem arising with the locomotion of the Xenohox Gazelle; because its locomotion requires that it be constantly spinning, its body will end up acting as one huge gyroscope, which'll play havoc with its maneuverability. On the other hand, that's a problem that arises with some of my own fictional creatures (reduced to their most basic shape they're spheres rather than wheels, but the same principle applies), so I guess it's not really fair for me to criticize.

The Möbius fish, on the other hand, is an amazing concept; I would love to see that creature animated. I wonder how rapidly such a beastie might be able to swim? I picture it as moving something like a jellyfish, traveling at a slow pace with brief, regular pulses of speed, but it'd be fascinating to see an exploration of that bauplan adapted to faster motion--flight, say. I imagine that that would be very satisfyingly alien, considering that a human observer would not only find the bauplan bizarre, but (if they encountered a living, moving speciment) would have great difficulty figuring out what the bauplan even WAS.

Jan said...

It would be nice to see xenohox gibbons. Or maybe birds...
The evolutionary path to this kind of movement is hard to imagine, but basically it is a rolling animal going sideways, and we have already seen some rolling animals with mouth on their side, so it is not unimaginable.

Still one axis left untouched. I have read some SF story about humanoid aliens with two faces and four hands, spinning around their axis during walk, but cannot remember the name of the story, could some of you help me?

Sigmund Nastrazzurro said...

Evan: Aha! You already have animations of the Möbius/Moebius fish!? Perhaps, when I get to that post, we should combine forces, as I intended to make some myself as well.
In a first draft I wondered about whether these animals show 'handedness' as well. Anatomically it would not be necessary, or advantageous, I think, to adapt the animals to turning in one direction only. There is also a gyroscopic effect. In the animation I wished to keep the lifted legs as close to the body as possible instead of sticking out as they do now when in the 'swing phase', but the programme really is only an adaptation of one meant for linear movement. I did not have the time to redesign the leg movement. I d not know whether or not thomastapir considered such issues. He wrote that he would not be able to respond for a few days, but perhaps he will let us know later.

Ronan: the loop design is definitely very alien, but it is not compact as body shapes go. perhaps such open designs are indeed vulnerable, and you could also think that this design involves a high surface to volume ratio, making it less suitable to conserve heat, or moisture, but perhaps it lives where that is not a problem.
As for the gyroscope effect, I wonder how large that is. I do not see myself taking the time to do any calculations though...

So far my thoughts on the Moebius/Möbius fish are like yours; I doubt it can go fast, but it would make a great jellyfish analogue.

Jan: Perhaps thomastapir has thought about the origin of the movement. Perhaps it started with body axis vertical, with three vertical stumpy legs, so the animal would move like a dancing dervish. The need for speed could have it leaning towards the direction of movement. Could that be how its starts a run from rest?

Anonymous said...

I too find the presence of the large loops rather strange; there must surely be an anatomical reason for their presence beyond simple evolutionary heritage, otherwise one would expect them to become more compact or streamlined (much in the same way that the hole through the center of the vertebrate 'torus' is looped, segmented and outpocketed into a variety of organs).


Nicky said...

Sigmund, I think I found the perfect place to get New Hades books to exist: As for the Xenohox gazzelle, I think to move like that would require alot of balance and not to mention the notion that a torque would be required for that kind of moment.

Anonymous said...

Isn't "snap shot" and the brain piecing things together what happens when we rapidly move our eyes? Or am I wrong..?

Sigmund Nastrazzurro said...

Nicky: Thank you. I will keep a link in place.

Anonymous: Well, yes, a 'saccade' is a very fast eye movement meant to direct the eyes to a new visual stimulus, and the processing takes place afterwards. But in man there are five systems dealing with eye movements, and if you wished to adapt them for the Xenohox Gazelle, saccades woukd be useful, but so would the 'optokinetic system', in which a moving visual scene induces a corresponding eye movement. In the *Gazelle, counterrotating yes could be used to negate part of the head's turning, and you could use a saccade to flick the eye back again to its starting position. You cannot see during a saccade, but if the eyes would not make saccades simultaneously, vision woud not sufer much.

Anonymous said...

What effect would it have on the creature's movement if there were a second set of three limbs on the 'head'? Perhaps arranged in an alternating pattern relative to the rear limbs so that one a leg from one set would touch the ground while all of the other set were in the air?

Sigmund Nastrazzurro said...

Anonymous: I think it would mostly have an effect similar to that of turning a biped into a quadruped. It would be more stable and might be good for heavy animals.

Petr said...

I know this may not be the most apropriapte place to ask this question, but since there is a discussion about strange body plans in the comment section, what are your thoughts on monopods - single-legged creatures? They may be incredibly out of place and doomed in a shared environment with bi(and more)peds and there they may be the first candidates for extinction, but if the only dominant creatures were monopeds, would the limitations and disadvantages of having a single leg only matter at all? not being able to get up after a fall, certainty of death if leg gets broken... or would these problems put monopods to such pressure that nature would select against them completely?
If you think about it, if a cheetah trips in a pursuit of a gazelle, it has no dinner that way, and if this happens more times in a row, the cheetah will die eventually. If the gazelle trips while being pursued by a cheetah, it becomes dinner, no matter how many legs it has.
and even if you have more than one leg, having one of them broken hinders you substantially, unless you are a lightwight arthropod with a buttload of legs ;)
so monopods, yes or no? :D

Petr said...

sorry for spamming, but the moebious fish is awfully similar to this floating robot created by Festo:

Sigmund Nastrazzurro said...

Petr 1: about one-legged animals. If that description means animals with a movement cycle in which the leg is in the air for a while, then I think there are quite a few problems. Harming the leg dooms the animal, as you wrote, and keeping balance is another. Wind would be a problem for very small animals. For larger ones, much energy would be spent moving up and down instead of moving forwards. The only solution might be low-gravity worlds and having toes that spread wide to provide some stability.

Petr 2: I first came across the Festo device, and was then informed by others that Thomastapir had been there first. There are comments to that on the Furaha comments of the end of April and mostly May 2012.

Petr said...

Thank you for your insightful response! =)

Could I have one request? I would really like to read more about electric animals. It's one of the topics you haven't talked about yet. =)
I would like to learn more about how their electric organs work, and why there are no terrestrial animals that hunt this way.
I would like to know if "biological tazers" are possible on land.
I suspect water is much better conductor and that's one of the reasons why all the electric animals live in water, but I was thinking about a terrestrial animal that squirts a fiber at prey and then uses this filament as a wire to stun it.
If you would be willing to make a post about this some time in the future, that would be really amazing. Thank you. =)