Re: bipedalism and AAH

J. Moore (
Fri, 5 May 95 23:24:00 -0500

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.

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.

In fact, bipedalism is definitely, at times, a "much better way to mover
around" than quadrapedalism, as it's seen, not only in humans, but in
quadrapedal primates when they carry things.

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.

Um> As for big cats, I
Um> have seen film footage of a leopard which chose (wisely, in my opinion)
Um> to seek easier prey when faced with the organized resistance of a
Um> forewarned troop of chimpanzees...and leopards habitually feed on
Um> primates: baboons and the like are a normal part of a leopard's diet.
Um> Quite possibly, the extreme level of social organization and "close-
Um> knitness" and "cooperativeness" of human social groups derives from a
Um> distant ancestor...if chimpanzees were as organized as humans usually
Um> are, I doubt any big cats would bother with them at all.

Chimpanzees do not seem to be overly afraid of big cats; besides the
cases of chimpanzees occasionally sleeping on the ground while in
leopard country, there are other reports that show their reaction.
Kortland did a test in the sixties with a stuffed leopard with a chimp
doll in its paws; two female chimps threw sticks at it, apparently
distressed at the plight of the "youngster". Bands of chimps have been
spotted screaming at lions (from a distance) but holding their ground.

Then there was that leopard den. A band of chimps went over to a
leopard den (sounds like "a gorilla walked into a bar..."), well, they
really did (if I remember the time and place correctly it was at Mahale
in 1982) and started screaming up a storm outside the den. This chimp
group included not only adult males, but also females and young. From
the sounds inside, the researchers observing this determined the mother
leopard was inside at the time (but they didn't crawl in and check for
some reason ;-). A couple of male chimps did, however, and dragged out
one of the leopard's babies and beat it to death.

Chimpanzees are not so afraid of large cats as we might reasonably
suppose them to be. [that's understatement, in case you don't recognise

Um> >>>Again, why would they walk bipedially when it is such an
Um> >>>inefficient means of transportation?

I do hope we aren't going to see this incorrect, unsupported, and
disproven claim again ;-(

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

Um> >>warning had a better survival rate, and so bipedalism was a favored
Um> >trait in the population.

As occasional bipedalism is now for chimps and other primates, partly
for this reason.

Um> >Evolution takes a long time. And lost of body hair and subcutanous fat
Um> do
Um> >not fossilize, so I think it is difficult to determine whether the P.
Um> >monkey "shows a trend in this direction".

In any event, Caroline Pond (who is acknowledged as a leading edge
expert on fat and who Morgan cites as support of her views even though
Pond's work directly and explicitly contradicts the AAH) has shown
that human fat distribution is like terirestrial primates:

"The sparse data on the 'natural' distribution and abundance of adipose
tissue in primates show that the basic anatomy of human adipose tissue
is similiar to that of terrestrial monkeys, and so was probably
inherited directly from their primate ancestors."

"Anatomical, ecological and biochemical information provides no evidence
that the distribution of adipose tissue in modern humans has evolved as
an adaptation to thermal insulation, as required by the Aquatic Ape
Theory, or as protection from mechanical damage."

(Pond, 1991: pg. 193)

Pond, Caroline M.
1991 "Adipose Tissue in Human Evolution", pp. 193-220. *The Aquatic
Ape: Fact or Fiction?* Edited by Machteld Roede, Jan Wind,
John M. Patrick and Vernon Reynolds. Souvenir Press: London.

Now let's not hear that disproven "quadrapedalism more efficient
than bipedalism" nonsense again, okay? ;-)

Jim Moore (

* Q-Blue 1.0 *