*why* are apes stronger than people

[Padeye]

It seems to be common knowledge that apes are pound for pound stronger than humans. What are the physiological differences that make this so?

[bordelond]

Cecil has addressed this in a past column. Let me see if I can dig it up.

[SCSimmons]

Can’t answer your question, but here you can see that it’s not just ‘common knowledge’, but documented fact …

[bordelond]

Here’s thae article I was thinking of:

http://www.straightdope.com/classics/a1_001b.html

Cecil merely mentions “superior muscle structure”, though. There’s not much more detail available in that column.

[Padeye]

Thanks. I’ve read that column but it doesn’t go into the why I was looking for.

[bordelond]

Superficially, [url"http://friendsofwashoe.org/textsite/aboutchimpst.htm"]Friends of Washoe says:

Chimpanzees have robust bodies and powerful arms, and because of their dense bones and muscle tissue, chimpanzees’ upper body strength is 8-10 times stronger than that of humans.

Also, a more scholarly cite:

The most striking difference between the chimpanzee and human shoulder is in the proportions of the scapula. Human arm strength, much less powerful in movements when in a raised position, is reflected in the shape of the scapula that provides attachment surfaces and lever arms for muscles.

…

The chimpanzee forearm is relatively long in comparison to humans . Chimp radius and ulna are more curved than in humans and the chimpanzee distal radius has a radiocarpal joint surface that diverges medially. The major differences between human and chimpanzee limbs are contrasts in relative proportion. Chimpanzees have large powerful arms, slightly longer than their very short legs. Human arms are about 70% as long as human legs.

…

The chimpanzee hand is notably different from the human hand in the relative length of its digits. The chimp thumb is much shorter than in humans, phalanges exhibit much more robust insertion areas for flexor tendons, and metacarpals have transverse ridges across their heads that limit dorsiflexion.