Re: AAH: humans long-distance runners?
Phil Nicholls (pn8886@csc.albany.edu)
4 Dec 1994 00:41:26 GMT
In article <jlittle-3011941644580001@47.69.129.57>,
Jim Little <jlittle@bnr.ca> wrote:
>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.
If I were to design a system from scratch I can no doubt think of some
way to improve on the current design. However, evolution does not
design organisms from scratch. It is constrained by what it has to
work with. Sweating in humans is primarily a thermoregulatory event.
How do we know? Because it occurs when the body is overheated, often
without regard to the external air temperature.
>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.
Morgan forgot to mention that tears and sweat are hypotonic to blood and
tissue fluids. That means that there is less salt in sweat than there
is in blood plasma, which means that neather sweating nor crying are
likely to be excretions. Consider also that if they were excretions
then you would start to sweat after eating salted peanuts or start t o
cry after some salted popcorn.
We sweat because we are hot or nervous. He cry because we are emotional
or because our eyes are dry and irritated.
Stick to the facts.
--
Philip "Chris" Nicholls Department of Anthropology
Institute for Hydrohominoid Studies SUNY Albany
University of Ediacara pn8886@cnsunix.albany.edu
"Semper Alouatta"
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