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Re: bipedalism and AAH
Phil Nicholls (pn8886@csc.albany.edu)
28 Apr 1995 00:27:41 GMT
Before I post this reply I would like to make a suggestion.
Rather than continuing the same old songs, much to the
annoyance of other SAP readers, I suggest Elaine Morgan write
a FAQ outlining the evidence supporting the AAH and I will
(since no one else is interested, I assume) post the counter
arguments I have been posting here. This way, the next time
someone askes about the AAH we can say: Read the FAQ, the way
they do in other newsgroups and only address those points not
covered in the FAQ. I belive Danny Yee is keeper of the
archives, is he not?
Anyway, back to the show:
Elaine Morgan writes:
> Answers to pnich:
> You ask why quadrupedalism would still be a n easier option
> for a climber coming to ground. Because it had evolved to be a
> climber.(Not a leap-and-cling merchant like the indris or the
> intermembral index would be different). As a climber its feet
> wouldn't be flat, its knees wouldn't lock, its pelvis would be
> all wrong, its spine would still be cantilevered, its head
> would be stuck on at the wrong angle instead of balancing on
> top of its head.
Why then do gibbons and spider monkeys ALWAYS walk bipedally
when they come to the ground? The answer is that they use
their forelimbs for suspension more than climbing. They are
not weight-bearing structures. The best hypothesis I have
seen is that hominids evolved from an ape clung vertically to
tree trunks (not a vertical clinger-and-leaper, but a
suspensory feeder.
No, it wouldn't have the characteristics of a hominid. If it
did, then it would BE a hominid. However, as I have often
pointed out, the behavior usually precedes change in
morphology and not the reverse.
> You quote Rodman and McHenry to the effect
> that bipedal ape walking consumes no more \(and no less)
> energy than quadrupedal ape walking. On the other hand,
> bipedal ape standing comsumes more energy than quadrupedal ape
> standing. Bipedal ape running consumes a great deal more
> energy than quadrupedal ape running and it is also much
> slower. That last fact alone could mean the difference between
> life and death on the savannah.
It is important to keep in mind that the Rodman
and McHenry data on quadrupedal apes is taken from
chimpanzees, who are knuckle-walkers. More generalized apes
lacking the knuckle-walking adaptation would undoubtedly be
more efficient both running and walking.
Also, I have not been arguing a sudden jump out onto the
savannah. If you have read my posts then you will remember
that I am suggesting that early hominids occupied an
ecological zone where forests meet savannah. As conditions
became drier and forests began to shrink these peripheral
environments became less optimal. It probably began short
excusions out onto the savannah. Perfection of bipedalism
enabled longer excursions and eventually, by the time of Homo
habilis, occupation of savannah environments.
> Wheeler. I heard him say it in a lecture at Sheffield.
> Precisely what he said was that 0.7 litres of water a day
> would replace a day's water loss "if it (the hominid)
> retreated into the shade for a four-hour period in the
> afternoon." Of course perhaps it would be able to consume
> more than 0.7 litres per day. If you ask me it could consume
> all the water it needed or wanted because it lived by the
> lake, or the river.
Most animals on the savannah live NEAR a lake or river and
visit them regularly. Few animals actually live at the
waterhole or riverbanks because those areas tend to be haunted
by predators as they are today.
> Right. so Wheeler now concedes that bp didn't evolve on the
> savannah but on the forest edge, the interface. All you are
> now asked to believe is that this ape, with its brain
> allegedly hypersensitive to overheating, took its first
> lessons in bipedalsim by choosing to go out and stand up in
> the midday sun, presumably only retreating to the shade of the
> trees when the heat was off. Now why would it do that? You
> keep saying that Wheeler's hypothesis was tested. It was
> tested with an inanimate model not a living animal. Forgive
> me if I think that you cannot extrapolate like that
What Wheeler tested was his proposal that bipedalism reduces
thermal load. Yes, he used an inanimate model rather than a
living ape, which in my view is a good thing. These data do
not need to be extrapolated unless you can tell we why a
bipedal ape would absorb more heat than a bipedal model.
Of course we can constrast this with the aquatic ape
hypothesis that has not be tested nor is it likely to be
tested because it doesn't produce any good predictive
statements.
Protohominids didn't just stand in the mid-day sun, they
walked from the forest to that clump of trees 100 meters
away because there was FOOD there.
Adrienne Zihlman.
> She wrote "The Wading Ape" in Oceans in May 1980. I asked for
> space to reply, Answer: sorry, can't be done. She wrote "The
> leakey Logic of the Aquatic Ape" in the BBC Wildlife mafagzine
> in April 1986, refuting AAT. And that was strange because how
> were her readers to know what she was refuting? At that time
> the BBC had never by word or deed led its viewers, or its
> radio listeners, or its magazine readers to suspect that such
> an idea as AAT even existed. Total taboo (broken for the first
> time recently by Desmond Morris after a fierce tussle with the
> top brass.) So it seemed a bit one-sided and I asked for
> space to reply. Answer: sorry, can't be done.
Well, I first heard of it when I say you make an appearance on
the Dick Cavett Show (1972 I think, maybe 1973). Besides
that, you have written, what, four books now so I think Oceans
may be forgiven for not giving you space. I imagine more
people have read your books than have read either of Zihlman's
articles.
> Zihlman's motives, like pnich's are entirely honourable. She
> wants to warn and protect people against what she sincerely
> belives is a dangerous heresy. When she started the AAT case
> did have enough leaks in it to look easily debunkable. I
> b same vein as Robert Ardrey.
It causes some ripples in bookstores but hadn't really had
much of an impact on paleoanthropology. As a matter of fact I
was recently rebuked by a faculty member here for spending too
much time with that "aquatic ape nonsense."
> "The Aquatic Ape: Fact or Fiction? "
> Bipedalism: an extant model. It is noteworthy that stationary
> bipedalism in feeding behaviour or in sentinel behaviour has
> never led to locomotor bipedalism, nor has diplay behaviour.
> But wading behaviour has. In my AAT video there are shots of
> proboscis monkeys wading bipedally through water, followed by
> shots of a group of proboscis monkeys walking bipedally on the
> forest floor - not displaying , not carrying anything, not
> feeding, just locomoting from one place to another in their
> own wild habitat but doing it on two legs.
It is also noteworthy that proboscis monkeys have not lost
body hair, gained subcutaneous fat. They are able to walk
bipedally without shortened pelvises, realigned muscles or
locked knees. In effect they do what nearly all primates do
from time to time -- walk bipedally. I have been arguing this
point forever it seems. Behavior before morphology.
> You keep saying "We know that the hominids moved from the
> forest to the savannah". You are being economical with the
> truth there. You know the LCA livbed in the forest. You know
> the hominids appeared, strangely transformed, a couple of
> million years later. You do not, repeat not, know where they
> spent the interim.
Actually the gap between the common ancestor (which is what I
believe "LCA" is supposed to be) and first hominid is shrinking.
You now have only a million years to squeeze the aquatic phase
into and if the rumors I am hearing are anything close to
correct you may have less than half a million years.
> And you cannot prove that they were not "on the savannah"
> in exactly the same sense as the hippoptamus is on the
> savannah.
Ah, yes I can. Hippos are qradrupeds, at least they were the
last time I looked (not counting one of the numbers in
Fantasia).
--
Phil Nicholls "To ask a question you must first
Department of Anthropology know most of the answer."
SUNY Albany -Robert Sheckley
pn8886@cnsunix.albany.edu SEMPER ALLOUATTA
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