Re: bipedalism and AAH

Kevyn Loren Winkless (
6 May 1995 19:34:59 GMT

In <> (J. Moore) writes:

>Um> In <> Troy Kelley <>
>Um> writes:

>Um> >In article <3o5rd0$> Kevyn Loren Winkless,
>Um> > writes:

>Um> >>You're missing the point. It's not a matter of whether or not the
>Um> >>generalized apes moving bipedally are more efficient than quandrapedal
>Um> >>apes, but rather that for generalized apes moving bipedally is more
>Um> >>efficient than moving quadrapedally _because_ they do not have the
>Um> >>knucklewalking adaptation. Given a generalized ape, adapted to a life
>Um> >in
>Um> >>the trees, walking on two legs or walking on all fours is six of one
>Um> and
>Um> >>half-dozen of the other; neither is particularly comfortable.

>Actually, as Phil Nichols has pointed out (repeatedly!) in this
>newsgroup, actual tests with chimpanzees has demonstrated that even for
>those knuckle-walking apes, bipedalism is no less efficient a mode of
>getting around. So the entire above argument is meaningless; the
>question has been answered by scientific experimentation.

Yes, this is the case, but this also assumes that the common ancestor was
a knucklewalker. My explanation above covers the possibility (which
seems to have been repeatedly asserted by AAH proponents) that this
ancestor was as yet just a generalized primate, unspecialized for either
knucklewalking or bipedalism. The question I was replying to was: why
would an unspecialized primate develop toward bipedalism rather than
quadrapedalism (or something to that effect)? Anyway, we're saying the
same thing (I think you might have confused what I wrote with inclusions
from previous posts).

>Um> >The simple fact is that quadrapedalism is a much better
>Um> >way to move around than bipedalism, therefore humans would have needed
>Um> >intense selection pressures to adopt such a unusual means of
>Um> >transportation.

>This doesn't even make sense if the above-mentioned testing hadn't been
>done (who *says* it's a "much better way to move around"?), but since
>the tests were in fact done, and reported here many more times than
>once, and in response to, among others, one of the posters (Kelly), he
>at least should know by now that this statement is simply untrue.

The problem is that since specialized quadrapeds are generally faster etc
than humans, most people assume that this proves quadrapedalism is more
efficient than bipedalism. It doesn't. It proves that quadrapeds who
are specialized for long distance and/or speedy running (ungulates, wolves,
big cats) are faster than bipeds who are specialized for walking and

>Um> >This reminds me that some of the AAH theorists have hypothisized that
>Um> >some homonids evolved separately on an island off the coast of Africa.
>Um> >This is starting to have more appeal to me when one considers what easy
>Um> >prey our bipedal ancestors must have been to most big cats and other
>Um> >carnivores.

>Um> Shoreline habitats have their own share of predators, particularly with
>Um> the extremely aquatic lifestyle often proposed by AAH
>Um> proponents...sharks etc.

>And crocodiles. Of course one of the AAH adaptive scenarios has AAs
>outswimming sharks; but since sharks swim at over 20 mph, and the
>fastest Olympic athletes can only manage a little over 5 mph
>(5.1048 mph in the 1992 Olympic Games 50 meters to be exact), that
>seems mighty unlikely.

Not to mention that nile crocodiles are known to run down unsuspecting
gazelles from time to time...they're a lot faster than you might think,
they just can't keep it up for as long as mammals can.

[snipped chimps and big cats...yep, social organization, a little simple
tool use and simple ape cussedness is enough to put the fear of "og" into
any self respecting pussy, no doubt about it!]

>Um> >>walked upright so as to see above the terrain and note approaching
>Um> >>predators, like gophers.

>Or like chimps, who do just exactly this. Baboons too, for that

I wasn't sure about baboons, and I wanted to be sure I used a properly
grasslands animal. Actually, I can't think of very many "short" mammals
who don't habitually adopt a bipedal stance when in tall grass or brush.
Even my cat does it, to aid in navigation and to see where the grass is
rustling when he's hunting and lost direct sight of the prey.

...Kevyn Winkless.

"...I drank WHAT!!?" - Socrates