Re: Bipedalism and endurance (Re: AAH - enough already)
Pat Dooley (patdooley@aol.com)
6 Dec 1994 01:45:16 -0500
In article <3a3sku$5jp@geraldo.cc.utexas.edu>, Robert Scott
<rscott@mail.utexas.edu> writes:
1) Humans can outlast other animals in tests of endurance.
Citations required. Horse vs human? Camel vs Human? African hunting dogs
vs
humans?
2) All humans acclimatise to heat quickly, but not to cold.
That's why we can't live in Cleveland but just love Death Valley.
Seriously,
if you are going to make such a claim, cite some comparative evidence. How
do humans stck up against Chimpanzees, for example.
3) Bipedal posture exposes more surface area to be cooled and
keeps the brain and most of the body above
the hotter area just above the ground.
The heliotropic ape theory. How's this for a test. We'll tether you and a
Baboon out in the tropical sun and see who succumbs to heat exhaustion
first.
4) Humans posses eccrine glands which are more efficient in
cooling the body than apocrine glands.
The converse is true. Eccrine sweating is uniquely human. It is slow to
start,
and hard to shut down. The excess moisture productive is extremely
wasteful
compared to apocrine sweating. All other sweating mammals rely on aprocine
glands to sweat.
5) Humans have more sweat glands.
>From a biological point of view, they have very few sweat glands. They do
have
an abundance of Eccrine glands that have been co-opted for sweating.
6) Lack of dense body hair facilitates cooling.
The converse is true. Fur provides a greater evaporative surface.
7) The efficiency of sweating as a cooling mechanism is greatly
reduced in humid, wet climes.
The AAH, so far as I recall, suggests that human sweating was a post
aquatic
human evolutionary innovation that arose because fat, hairless, acropine-
glandless animals had to find some way to cool down. Evolution gave us a
quick and dirty fix; profuse eccrine sweating. It may have been a
refinement of
an earlier salt excretion mechanism.
Pat D rehashing old material
Draw your own conclusions.
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