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I've designed an alien race of bipedal humanoids with digitigrade legs.

This race's advanced scientific progress means that they use traditionally human-associated technology, or similar (such as vehicles.)

It did however occur to me that the double-jointed legs may inhibit certain activities, or negatively influence other aspects such as the species' ability to balance.


So essentially, what are the advantages and disadvantages of having digitigrade legs?

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  • $\begingroup$ But.. if you simply walk on your toes you could essentially simulate how a digitigrade leg would be. Your ankle would serve as that lower joint. You should also do some research into ostrich legs. $\endgroup$ – Aify Apr 24 '16 at 3:07
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It all depends on what kind of planet that race has developed on and how they have evolved.

Pros:

  • generally quieter footfalls

  • much faster running

  • more agility overall

Cons:

  • it could be uncomfortable for them to use some kinds of vehicles and technology in general as we know it, so it is necessary to completely (or almost completely) rethink any piece of technology that involves the use of legs: for example, cars as we know them would be unpractical for digitigrade-legged aliens, since there wouldn't be space for them to properly move

Overall, it could be well explained by the fact that their planet is "savage" in large part and that they had to evolve faster legs to escape natural predators in the past. For instance, there could be a species of aggressive flying beasts that used to hunt them in their prehistory, forcing this alien race to develop better speed and reflexes over the millennia to manage to dodge the first attack of one of these beasts and go hide in one of their planet's many natural caves while the beast turned around for a second try.

Regarding the use of vehicles and such, they may have simply developed technology suited for their anatomy: for example, their "cars" could be something like ours but with pedals at chest height (to be more comfortable using them with digitigrade legs) and a joystick rather than a wheel, to make more space for the legs.

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    $\begingroup$ Hi Hankrecords, and welcome to Worldbuilding and Stack Exchange. Could you expand on the point that using technology in general would be uncomfortable for a digitigrade hominid species? I can perhaps see how something designed for plantigrades might be a less than perfect fit for a digitigrade species, but surely they would be designing their technology to fit their physiology just like humans have. I think that an edit to clarify this point could take your answer to the next level. $\endgroup$ – a CVn Apr 24 '16 at 14:19
  • $\begingroup$ Thanks for the tip, I edited the answer to clarify what I was trying to say. $\endgroup$ – Hankrecords Apr 24 '16 at 16:14
  • $\begingroup$ You don't evolve inteligence by running away. You turn around and fight as a group! If it kills somebody, deny the body by attacking in return and they'll think twice the next time whether it is worth the effort to hunt your kind. $\endgroup$ – Nick Dzink Nov 19 '17 at 22:02
  • $\begingroup$ @NickDzink I didn't say they necessarily kept running away. The agile legs could be a leftover of evolution, like the pinky finger in human feet, only a little more useful $\endgroup$ – Hankrecords Nov 20 '17 at 10:17
  • $\begingroup$ down side less leg flexibility, the "indian style" sitting position is impossible for a digitigrade. humans can climb a tree or pole by flexing the hip out and ankle joint inward which is also impossible for a large digitigrade. $\endgroup$ – John Aug 16 at 15:11
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I think that the answers here are pretty good. leagues better than this one, but I thought I'd give you something I found during my travels

A Large jpeg image by artist Jesseth detailed realistic portrayals of digitigrade bipeds

I would just comment this, but last time I commented a possible answer it cost me 540 reputation.

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    $\begingroup$ I love this! thank you, this will be very useful in future designs. $\endgroup$ – XenoDwarf Jun 23 '16 at 4:38
  • $\begingroup$ @TunaDragon The link at the top will send you to a higher resolution that's to big to upload here $\endgroup$ – TrEs-2b Jun 23 '16 at 4:41
  • $\begingroup$ Therozenosaurs would be an example of an upright or at least semiupright digitigrade biped. Their hip bones almost 90 degrees to get the tail to stick out horizontally. Dinosaurs are weird though they have to have the tail stick out because that is where the leg muscles attack, mammals have buttocks instead. static.squarespace.com/static/51bf1cd3e4b0a897bf54112b/… $\endgroup$ – John Aug 16 at 15:05
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In a nutshell: digitigrade legs are faster, plantigrade legs are more stable.

Digitigrade legs get extra leverage from their ankle while running, giving them a 'spring' in their step. However, they lack the weight-bearing ability of a solid plantigrade stance.

Your digitigrade bipeds would probably be easier to knock over than humans, but would make up for it with faster running and jumping.

It is possible that they evolved from fast running sprinters (like cats) rather than persistence hunters (like humans), but this is not necessarily the case - a lot of plantigrade vs digitigrade has more to do with ancestry than the specific advantages of each stance. For example, you'd expect elephants to be as plantigrade as it gets, but they are actually partially digitigrade unguligrades because their much smaller ancestors were (their digits became much thicker to bear their weight instead).

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enter image description here

Well this here might help as well. It comes from the Twokinds webcomic. I would post a more detailed explanation but I'm still recovering from my family's Christmas feast. ;3

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Also look @ how Draenei walk & stand (as designed by Blizzard, for World of Warcraft). They are also digitigrade & even have hooves. Best of all, because they are animated & a lot of ppl draw inspiration of them, it will be easy to find examples & even see, how they move, walk, live & (allmost breath)...

  • 1 con I've found too: If you ever saw Robocop, with ED-209 (whic also looks digitigrade), I think bipedal digitigrades have a hard time, doing stairs (especially downstairs), if the steps are to short & they probs will fall on those stairs, as a digitigrade can't support directly on it's heel (no extra bones/flesh there), as it is not ment to be stood on, directly, like a human heel...
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    $\begingroup$ Welcome to Worldbuilding.SE! We're glad you could join us! When you have a moment, please click here to learn more about our culture and take our tour. Thanks! $\endgroup$ – JBH Mar 28 at 17:30
  • $\begingroup$ Thanks for the answer! One thing though, since the Draenei walk on their nails they would actually be unguligrade, not digitigrade (doesn't mean they're not a good example). Also, I thought the ED-209 fell because it's feet were big enough to make the stairs a slope, which wouldn't be a problem for a human-sized digitigrade. $\endgroup$ – XenoDwarf Mar 29 at 5:58
  • $\begingroup$ Do you use your heels on stairs?!? I'm puzzled, because I definitely don't. Ok, when I stop, I do use my heels, but never when ascending or descending stairs. That would feel dead clumsy to me. Do you really have such a different walk that you actually need your heels on stairs? $\endgroup$ – cmaster Mar 30 at 23:52

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