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02:31 28-01-2012
Antwan
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hi , i am sorry if my message is not very helpful, but i love your website. It is so cool. I kind of want to try and draw some of the Allotaurinea in your "About section. I would like to see some of them in your "Land" section. They are really cool. Again, sorry if my comment doesn't do you any good. Your work is still breathtaking.
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02:57 26-01-2012
Spugpow
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I noticed a slight mistake on your links page. It says that Alex Ries' webpage hasn't been updated since 2007, but he did in fact add a lot of new artwork not long ago.
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13:46 25-01-2012
Mario Ferraro
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Where can I download the add on Furaha? (:
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09:58 14-01-2012
Jan
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SN: I do not want to ruin the surprise moment, but I think that the problem of the right movement of hexapod is quite crucial. Personally I can not imagine other pair than the hind one to provide propulsion force. It is a question if the unattached hind legs can still do that. If so (after all gibbons or birds use them more than the hind ones), it could have other advantages than the shock absorption - it could allow greater movability of the hind legs, with the function similar to mammalian flexible spine.
But the exact function of the first two pairs is still a problem. Could it be that the Avatar had it parcially right and that there would not be such a difference in their movement? First the middle one beat the ground, than the forelegs works against the inertia and stabilize the body. Sorry if it is one the unpublishable surprises.
I would like to say that I am talking about The Runner, not some kind of animal which could be very fast occasionally (like hippopotamus or crocodile) but is not specialized to it.
Btw, is the book mostly done or is it still work in progress?
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17:44 13-01-2012
Sn
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Dras, if so, that is a coincidence. All shapes were designed first on paper but afterwards a random computer process was involved.
Jan: quite right. I did not say much about the 'unpublished' paintings to keep a bit of the surprise intact.
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08:09 13-01-2012
Jan
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The "mowers" in the picture from the article seem to show unattached hind legs quite well.
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01:26 13-01-2012
Drás Researcher
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Is it just me or does Bogoria look like Sweden/Norway and Tendaguru looks like Alaska?
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16:27 08-01-2012
SN
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Evan, I forgot: you indeed cannot see well how hexapod limbs are attached in any of the published paintings. Still, it's there.
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16:20 08-01-2012
SN
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About sight and Barlowe's expedition: I reread my copy (first printing 1990), and it said that there was a 'planet-wise lack of true eyes'. Also: 'optical sensory organs are absent, ...supplanted... by a battery of sonar and infrared faculties.' There is also a lateral line system of pressure receptors and numerous tiny infrared receptor pits. Furthermore: '...biolights, heat-radiating bioluminous spots that appear quite vivid to infrared sensors.' As for the likelihood that sighted animals would overcome the blind ones quickly, the text states that all these senses evolved to become so good that the sighted ones did not have an advantage in 'Darwin IV's thick primordial mists. Now the mists are gone- but so are the optically-sighted animals'. I am not convinced, and wonder whether eyes might still outperform infrared senses in a thick mist.
Leg suspension: I do not think the causes and consequences of how a limb skeleton is attached to the body skeleton are well known. In fact, I could not find any papers on the matter, which is why I turned to McNeill Alexander. I thought that suspension by way of muscles would be costly in energetic terms, and the only gain I saw would be that the system would act as a shock absorber. If so, you do not want propulsion forces to be absorbed as well, so you would not expect to see muscle suspension in limbs with a primary propulsive purpose. Then again, perhaps the muscle suspension of mammal front legs is simply part of the body plan.
I assumed that shock absorption might be a good thing, so I kept that. The next choice was which limbs should be so equipped. I doubt that there is a imperative need to equip hind limbs with more propulsive force than other pairs; but again some sort of papers are hard to find. Cars seem to do work well with regardless of whether the propulsion comes from hind or from front wheels.
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15:04 06-01-2012
Jan
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There is a notice on "Walking with..." that the horse would fall on its face during bounding. This could be the explanation for hexapod run - it would be essentialy like gallop-bounding with six legs. Maybe an animation of antelope-like hexapod in run would help.
For less agile or arboreal animals (like marshwallow) six legs is probably better solution than four, imho. Lizzards seems to cry for six legs with every step.
Btw, there is also said that no large furahan animals walk like kangaroo. It is ok, but the efficiency of kangaroo walk call for the attention of speculative biology. There seems to be two big problems with it, moving during relative rest (the kangaroo way is, well, odd) and the ability of the joints and tendons to withstand the strain of hopping. http://en.wikipedia.org/wiki/Macropodidae Some ideas?
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22:58 05-01-2012
Anthony Docimo
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Jan - I'm not sure I understand you: how is the gyrosprinter like a cheetah? (also, wasn't the gyrosprinter a monopod?)
Evan - given that we're looking at Furahan fauna with their armor/fur/other on, it may be obscured to our eyes.
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14:53 04-01-2012
Evan Black
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I for one would be interested in seeing more about this subject, because 1) I don't fully understand the biomechanical ramifications of freely suspended limbs and 2) I have a hard time seeing the visual evidence for how furahan fauna have a different limb attachment than terrestrial life. Are there any existing blog posts that can help my ignorance?
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09:51 04-01-2012
Jan
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Yes, but look at the cheetah. It is more like gyrosprinter from Darwin IV, another type of biped. Maybe this is the reason for the movements of Avatar beasts, although their solution was quite uninventive.
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18:09 03-01-2012
SN
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Jan, as regards the 'necessity' of freely suspended pairs of limbs, even that 'necessity' is guesswork. Have a look at many quadruped dinosaurs, such as ceratopsians. Their front legs are connected to the sternum/ribcage and hence to the vertebral column. Could they run fast? many people think so...
As for how fast you can run with four or six legs is a matter of dispute. For very fast gaits there are phases in which no leg at all touches the ground, so these phases represent jumps. Increase the number of legs, and it will become more difficult to design gaits in which such jumps occur. One gait always remains, and that is to kick off with all legs at once. But that does not seem exactly useful for a millipede.
It is true that there is a tendency for animals to use fewer legs when running fast. Cockroaches and crabs come to mind: in both cases some run with two legs only, even though they have more. In larger animals this behavioural adaptation does not seem to play a large role. There are morphological adaptations in that some animals run on two legs, but it does not seem a universal trend. Gerbils, hares and kangaroos seem to lie on different points of a hopping trend. The absence of tetrapodal running species evolving towards bipedalism again suggests that the trend is weak. I thought it weak enough to mean that a need for speed does not readily result in the loss of a pair of limbs in hexapods.
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17:21 03-01-2012
Jan
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SN: I do not know the reason for the unattached front legs either. Flying vertebrates have very strong shoulder girdle for obvious reason, while fast runners lack the clavicle to allow greater mobility. But still, there is something upsetting about this design.
My original question about functional bipedalism or quadrupedalism is aimed at those hexapods that use all six legs and still seem to be fast runners. I like it. But is it realistic? Kangaroos, cheetah, or ostriches use very different ways to achieve high speeds, but furahan animals seem to be completely different. Even insects seems to be chosing bipedalism fot top speeds http://en.wikipedia.org/wiki/Facultative_biped
This is not mean to criticize the jingos design. Furaha without hexapods would not be Furaha.
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