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Re: AAH: humans long-distance runners?
Rod Hagen (rodhagen@insane.apana.org.au)
Thu, 08 Dec 1994 12:50:20 +1000
In article <jlittle-3011941644580001@47.69.129.57>, jlittle@bnr.ca (Jim
Little) wrote:
> 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.
Interesting that despite this "very wasteful and poorly adapted to its
function" cooling system, human beings manage to survive quite effectively
in everything from the rainforests to the Gibson Desert! Not many other
mammals are quite so adaptable. Ah, the power of culture!
I remember reading recently, though I can't for the life of me remember
where, an inteersting article which examined the biological efficiency of
water use by different human groups (white Australians, Aborigines etc.).
Anybody know of good source material in this area?
ps somebody ought to tell my father-in-law that "humans lack the instinct
possessed by many animals to seek salt when their bodies are lacking it".
He seems to search for it incessantly. Seem to remember the occasional
insatiable desire for a nice salty packet of potato crisps every now and
then when working out in the desert in extreme heat for a few days at a
time myself.
Cheers
--
Rod Hagen
rodhagen@insanity.apana.org.au
Rod_Hagen@maccontent.apana.org.au
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