From: Kevin Bluck (kevin.bluck@mail.com)
Date: Fri Jul 19 2002 - 10:38:40 MDT
> Since the Aquatic ape Theory was mentioned I did a bit of surfing. The
> following link seems to offer some sound objections to the AAT. Enjoy.
>
>http://aquaticape.topcities.com/firstpage.html
I've seen this page, and similar arguments against AAT.
A major class or argument is of the general form, "If humans evolved in
water, why aren't we more <<whatever>>?" One of Morgan's books has a title
page with a quote. It says something like (from memory, sorry): "Critics
say that if AAT it true, then why aren't humans more streamlined? My
response is, 'more streamlined than what?'" This is next to a photograph
juxtaposing a chimpanzee next to a human swimmer diving into the water.
Another good example is the question, "Why aren't we faster swimmers? We'd
be eaten by sharks and crocodiles." Well, you can make the same argument on
land. "Why aren't we faster runners? We'd be eaten by lions and tigers."
Humans may not be dolphins, but we sure do kick all other primate bootie in
the field of swimming. So, again, the operative question is, "faster
swimmers than what?"
Nobody is claiming that hominids were frolicking in the deeps with the
dolphins. Central to the idea of AAT is that humans *started* adapting to
an aquatic form, but before the process was complete, it was interrupted
and humans have been readapting to terrestrial existence ever since. These
things take time. I think we all know that dog/bear ancestors did not
metamorphose into sea lions overnight. It took tens of millions of years to
reach their current form. Ancestral forms of sea lions exist that show
clear signs of not being "as good" in the water as modern sea lions. Even
more interesting, hippos and whales have been recently linked by
geneticists as sharing a common ancestor. A good example of the different
paths water-dwelling mammals can take. They don't all sprout fins.
Other species exist which show similar "incomplete adaptation" syndrome.
Two good examples are pigs and elephants. Much like humans, they show
numerous leftover signs of an earlier water-based ancestor. Much like
humans, they now spend most of their time on dry land, but whenever they
come across a bit of water, they happily wade in and wallow. Most
zoologists agree that these species have "more aquatic" ancestors in their
history, and that the current land-dwelling forms have "deadapted" a bit
from the water. The closest living relative of the hippopotamus is, in
fact, the pig.
As a matter of fact, I think that is a pretty good point right there. When
people hear "aquatic mammal", they think of dolphins and seals, and start
comparing the "aquatic ape" to that standard. I think it would be more
appropriate to compare this ape to hippos and pigs, in terms of morphology
and habits. Perhaps it would be more accurate to call the theory the
"Wallowing Ape" theory. Hippos are certainly not "streamlined", and they
tend to walk on the bottom rather than swim, but nobody can deny they are
"aquatic".
Another class of argument, related to the "more whatever" type, is centered
about human's unsuitability for a fully-aquatic lifestyle *now*, millions
of years since we were forced out of the water. For example, they might
complain that modern human skin is not very waterproof (aka the "prune"
syndrome.) But, what is to say that our ancestors weren't "more aquatic"?
Who can say whether Lucy didn't have fully webbed fingers? That she
couldn't shut her nostrils? That her diving reflex wasn't much more
pronounced? That her subcutaneous fatty layer wasn't much thicker? Her skin
smoother and more waterproof? Unfortunately, those sorts of features are
very difficult to determine from fossilized skeletons. Especially if you're
not looking for them. Pigs would also have trouble living full-time in the
water now, but there is not much dispute that their ancestors were more
aquatic than the modern form. Why is it so hard to believe for apes?
Critics also do a lot of somewhat Clintonesque parsing. For example, some
critics seriously try to prove that humans are just as hairy as
chimpanzees, that we're not really naked animals at all, so the question of
why we're naked doesn't need solving. This is technically true; I
understand that we actually have just as many individual hairs as a chimp,
if not more. However, it is obvious to the smallest child that we are, for
all practical purposes, naked-skinned animals. Even Robin Williams. We may
have "fur", but it is too atrophied to serve any useful purpose. It's just
an irrelevant leftover. We might as well be as naked as Dr. Evil's kitty.
While I certainly agree AAT is not "bulletproof", I *do* think it is much
more "holistic" than the other explanations available. Land-based
explanations make humans *different* than every other land species, and
strive to explain away feature after feature that is just not found in the
land animal catalog. On the other hand, all these "strange" features that
make the human species so unusual are found in a variety of animals with a
watery past or present. Sure, one or two oddities can be explained away,
but how many features that any zoologist would associate with a water-based
mammal in any other species but man do you need?
--- Kevin
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