Re: AAT Theory

chris brochu (
15 Sep 1995 01:25:19 GMT

In article <439flr$> Tom Clarke, writes:
>Reconsider parsimony. Hypothesis 1 explains only bipedalism as an
>adaptation to the savannah (why aren't baboons bipedal?). Nakedness,
>subcutaneous fat, etc must be explained in some other way.

I'm no expert in primate anatomy, but I don't buy the idea that
subcutaneous fat and hairlessness indicate aquatic habits. Part of my
current job is roughing out vertebrate carcasses for a dermestid beetle
colony. I've seen subcutaneous fat in just about everything, especially
if the animal was someone's overfed pet.

Could it be that subcutaneous fat - if, indeed, humans have more than
other primates - results from our loss of insulating fur?

Why must hairlessness indicate aquatic habits? Elephants and rhinos are
not particularly aquatic, and are largely hairless; beavers, muskrats,
and otters spend most of their time in the water, but are trapped for
their pelts. In any event, why did we leave a great deal of hair in
precisely the places where an aquatic animal would want it least - on top
of the head, where it would get in the eyes; and around the mouth in
males, where it would clearly inhibit feeding.

The parsimony argument I was making had more to do with habitat than
habit - tree to land vs. tree to water to land. The "water" stage is not
preserved, and I see nothing in extant hominoids to suggest its presence.