The fallacy of compliant walking

[barehl]

Mammals walk with the gait that they're built for.

Well, yes, what exactly would be the alternative?

Humans are made to walk with mainly a straight leg, so that's how people walk.

Again after 3 million years of getting it right.

Assuming that Bigfoot would walk the same way is a mistake.

Based on a scary teddybear fantasy?

Such a small difference in the knee bend could be natural for an animal that isn't built the same as us. Basically, just because regular humans don't walk with a compliant gait doesn't mean that other upright primates won't.

Well, I'll make the point again. The straight leg is the most efficient way of walking. If you walk with a bent knee then fatigue will set in pretty quickly because your thigh muscles will be continually supporting your weight. Nor can you get any spring energy from this as kangaroos do because a stretchy tendon would interfere with accurate leg positioning. I posted video links to show what I was talking about. I do notice a distinct lack of video links with your post.

 

[barehl]

I'm 6'7" and discovered about 20 years ago that a compliant gait helps me to carry a heavy load, for example a packing box full of books.

If I were to carry that box on my head, I would walk upright with legs straight. But that's not how men carry boxes in my culture, so instead when burdened with a box of whatever, I often opt to use a compliant, knees-bent gait.

If this is common then you should be able to post a video link showing it. Also, what distance of carrying are we talking about? Carrying a hundred steps is not like carrying 10 kilometers.

 

[MikeG]

......The only other efficient two legged walkers are some of the flightless birds.

Not so.

 

[barehl]

Even fully flightless birds walk with a completely different gait than ours. They are way up on their toes with knees bent.

Right and flightless birds aren't really comparable because in addition to the digitigrade feet, their body mass is concentrated in the thorax whereas humans have substantial weight in legs and arms.

 

[barehl]

Not so.

Anteaters have the same problem that their front claws make it difficult to walk so they will also stand on hind legs alone. You can do that when you have a heavy tail to balance your weight. I wouldn't exactly call that efficient though.

 

[MikeG]

Anteaters have the same problem that their front claws make it difficult to walk so they will also stand on hind legs alone. You can do that when you have a heavy tail to balance your weight.

Which anteaters? South American giant anteaters don't do that, to my knowledge.

I wouldn't exactly call that efficient though.

I would.

But I'm not seeking to make a "pangolins-are-bipedal-therefore-bigfoot" argument. I was simply pointing out a really interesting and little known fact of nature in response to a slightly erroneous statement. I saw a pangolin in the wild some years ago, and it was only after a few minutes observation that I realised it was walking on its hind legs only.

 

[Ladewig]

A polite request.
In future threads, would you include the topic of the thread in the title or the first sentence of the OP.

 

[The Shrike]

I see pangolin bipedalism as facultative - kind of like hadrosaurs might have moved rather seamlessly between bipedal and quadrapedal locomotion. Pangolins appear to be plantigrade but heavily counterbalanced.

 

[Senex]

I thought at first this thread was going to try and poke holes in my dating rituals.

 

[barehl]

Again, in regards to science. You have articles like Insights into the evolution of human bipedalism from experimental studies of humans and other primates which states:

As a result, my colleagues and I have argued, as did Stern and Susman (1983), that compliant bipedalism may have been an effective gait for a small biped, with relatively small and weakly stabilized joints that had not yet completely forsaken arboreal locomotion (Schmitt et al., 1996, 1999).

This difference in locomotor styles between early hominids and modern humans appears to be associated with small, gracile and poorly stabilized hindlimbs in our earliest ancestors (Stern and Susman, 1983).

This doesn't sound like a quarter ton, ground dwelling animal. Are there gracile bigfoot?

It seems likely that the shift to a more robust modern skeleton seen in early members of the genus Homo reflected the adoption of a relatively stiff-legged gait.

The data described above strongly suggest that a relatively stiff-legged bipedal gait and associated physiological and musculoskeletal adaptations are not inherited from prebipedal ancestors or even from the earliest upright bipeds. These features are instead, specialized characters that evolved relatively recently.

So, again, a necessary adaptation for efficiency.