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I am considering a mid to large sized creature, the loping quhambo. Maybe eight to ten palms at the whithers and maybe five stone in weight. It is a proboscidean mammal of some sort, though quite possibly not related to the oliphant.

I am curious about quadrupedal mammalian gaits. I know there are different kinds of gait, varying with speed and that there are different "foot placements" involved. Specifically, I'm interested in a 6:2 ratio -- for every six steps the relatively short hind legs make, the rather longer forelegs take only two. This is why they're called loping.

enter image description here

For ordinary loping along at various speeds, is this gait realistic / plausible with respect to known mammalian locomotion patterns. If so, does any living or extinct animal walk like this?

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    $\begingroup$ I really doubt it, can't see any evolutionary advantage in short hind legs and long forelegs. Much more frequent the other way around. $\endgroup$ – Adrian Colomitchi Feb 21 '20 at 6:23
  • $\begingroup$ There is no way this is evolving, animals with limbs of different lengths just move the longer one through a shorter arc keeping all limbs in sync. there are many animals with limbs of drastically different lengths. what is more likely is that it will flex its back and swing both hing legs forward at once thus increasing the distance they move. $\endgroup$ – John Feb 29 '20 at 12:36
  • $\begingroup$ @John: Kangaroos move like this but in reverse. They use the short legs to anchor and swing the entire body forward. $\endgroup$ – Daron Feb 29 '20 at 13:30
  • $\begingroup$ I don't know about leg lengths, specifically, but dogs that have been bred to have lower hindquarters like you are depicting have all manner of hip problems. I question how realistic a creature like this could be. $\endgroup$ – Matthew Feb 29 '20 at 15:46
  • $\begingroup$ @daron which is very different than this, even in kangaroo, the limbs move 1:1 $\endgroup$ – John Mar 1 '20 at 13:35
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There is no way this is evolving.

there are many animals with limbs of drastically different lengths, none of them do this. With an alternating gait like that shown, limbs have to swing through the space occupied by other limbs during movement, if the limbs that cross paths are not all swinging at the same interval they collide and your animals falls, the ground is not uniform limbs end up displaced or slightly out of sync so a certain a amount of slop (space) has to be built into the gait.

Animals with limbs of different lengths move in one of two ways. First they swing the limbs alternatively (as drawn) and just move the longer one through a shorter arc keeping all limbs in sync.

Alternatively they swing the limbs in pairs (gallop or loping) and flex the spine back to increase the arc of the hind legs. That way they swing both hing legs forward at once thus increasing the distance they move. This allows for moving at more than one speed, but it is also way more efficient. Even gorilla who's hind limbs are half the length of the front limbs move this way. if the limbs can swing between one another, this is what they will use, but then the limbs have to swing as pairs (both hind limbs together, and both front limbs together) or both hind legs can collide with each other. The only way to get around this would be to make your creature ridiculously wide, almost wider than it is long.

Look at hyena, gorilla, rabbits,or hadrosaur locomotion, to see how animals with different limb lengths move.

enter image description here

Also here is a great video of someone reconstructing a gorilla run cycle

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    $\begingroup$ The limbs won't collide if the back shoulders are narrower than the front shoulders. Consider the humble kangaroo: youtube.com/watch?v=HWiLyIqcK24 $\endgroup$ – Daron Feb 29 '20 at 13:27
  • $\begingroup$ Of course the kangaroo uses a 1:1 gait when on all fours. But it contradicts your point about the legs having to swing through the space occupied by other limbs. $\endgroup$ – Daron Feb 29 '20 at 13:28
  • $\begingroup$ that is my bad for not being more specific. I will clarity. $\endgroup$ – John Feb 29 '20 at 13:41
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I think what you have here is a semi-bipedal locomotion. The rear limbs are used for propulsion. The fore limbs are used for balance. I would suggest that the weight balance would work better to the rear, but might not be there, depending on the evolutionary pattern.

I think there are similar techniques used by some apes. I could also cite human "cruising" behavior.

To me, the big question is: what caused to difference in limb size to develop? And what permitted the poor gait not to get them killed by predators? (I suspect either semi-arboreal or semi-aquatic.)

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No living animal walks like this

. . . at least none that I can think of. The long-limbs-short-limbs pattern makes walking more difficult so it usually only occurs when walking is not the animal's primary form of movement. For example:

enter image description here

enter image description here

enter image description here Kangaroos main (best to escape predators) form of movement is hoopping with only the back legs. Giboons main form of movement is to swing (brachiate) with only the front legs. When on the ground both animals use a 1:1 gait.

If you want to evolve an animal with an uneven gait I suggest start with the kangaroo and remove all predators, and all need to travel very fast or very far. Then the hopping movement is not needed, the animal converts to a mostly crawling movement, an thus evolves a more efficient gait.

The problem is that, with no predators or danger, there is no pressure at all, and no need to evolve to become more efficient.

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  • $\begingroup$ there is still a big reason to increase efficiency, competition with other kangaroos. $\endgroup$ – John Feb 29 '20 at 13:51
  • $\begingroup$ @John: The tricky part is I have said food is plentiful. So I'm not sure there is any competition. Maybe better crawling lets you fight other kangaroos for a mate better? $\endgroup$ – Daron Mar 2 '20 at 14:34
  • $\begingroup$ There is always competition, it doesn't matter how plentiful food is. $\endgroup$ – John Mar 2 '20 at 22:07
  • $\begingroup$ @John: There will always be some nonzero amount of competition. Whether it is enough to trigger such a strong change sounds like a much harder question. $\endgroup$ – Daron Mar 4 '20 at 12:45
  • $\begingroup$ Not really, even tiny advantages can yield large results, every calorie you spend on your gait is a calorie you could have spent finding or attracting a mate, growing offspring, ect. plentiful food just means animals keep reproducing until it is not plentiful anymore. $\endgroup$ – John Mar 4 '20 at 23:29

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