Re: thermoregulation in hominids
John Waters (jdwaters@dircon.co.uk)
17 Dec 1996 23:36:20 GMT
Newington Reference Library <fp96@dial.pipex.com> wrote in
article <32B6F521.5909@dial.pipex.com>...
> Thermoregulation in Hominids
>
> by Andrew Lewis
>
>
> The savanna can get very cold at night. It can be cold
during the day.
> How does this fit into the equation?
JW: Your concepts may be too simplistic, Andrew. For
example, the Australian Aborigines in Central Australia
live in a dry Savannah type of environment which can get
very hot during the day, and cold at night.
However, they are able to sleep through the cold nights
without any clothing, because of an evolutionary adaptation
known as Vasoconstriction. This means that the blood
vessels leading to the legs and arms are constricted in
cold temperatures. This maintains core body temperatures,
and reduces heat dissipation.
Ref: The Cambridge Encyclopedia of Human Evolution. Editors
Steve Jones; Robert Martin; and David Pilbeam. Cambridge
University Press. (1995). page. 50.
John.
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