Re: AAH: humans long-distance runners?
Jim Little (jlittle@bnr.ca)
Wed, 30 Nov 1994 16:44:58 -0500
In article <1994Nov30.182456.13459@henson.cc.wwu.edu>,
n8010095@henson.cc.wwu.edu (Phillip Bigelow) wrote:
> Troy Kelley <tkelley@hel4.brl.mil> writes:
[ cut to the bone ]
>> Humans sweat way too much and loose a great deal of water in the
>> form of sweat, especially when compared to other animals.
[...]
> Actually, this seems to be strong evidence _for_ a savannah existence, not
> evidence against it. Of course hominids stayed close to water in their
> early evolution. All primates do so as well, so that proves nothing.
> However, your claim that "humans sweat way too much" is inaccurate. Humans
> sweat just the optimum amount to fit in to their environment. Evolution
> created the ubiquitous sweat glands on humans. The fact that humans sweat
> more freely than other mammals is evidence that they _need_ to sweat in
> order to function well. There is no compelling reason, as far as I can see,
> for an aquatic hominid to sweat as prodigiously as modern humans do. I do
> see a compelling reason to sweat buckets if you are scavenging in an open
> field in the hot sun all day long.
>
> <pb>
I just have to jump in here, all sweating buckets does is remove buckets
of essential moisture from the body which must then be replaced. Water
that runs off the body in rivers does not cool any better than a very thin
film. A dog (and many other animals) can cool its entire body just by
panting (with associated cooling by evapouration present in its
exhalations). The human system of sweating is very wasteful and poorly
adapted to its function.
I can give you a reason for an aquatic hominid to sweat as prodigiously as
modern humans do, to eliminate excess salt from the body. This may not be
a _compelling_ reason but sweat and tears have been suggested to be
remnants of excess salt elimination mechanisms. Curiously enough, humans
lack the instinct possessed by many animals to seek salt when their bodies
are lacking it, despite the fact that they are so good at eliminating it
from their bodies (in sweat, tears, urine).
This topic is discussed in Morgan's AAT books.
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