Re: Why is Homo sapiens hairless?

T&B Schmal (
Mon, 11 Nov 1996 21:34:54 +0000

In article <>, Doug McKean
<> wrote:

> T&B Schmal wrote:
> >
> > Look at the environment of the new biped - what are the other
> > animals in it wearing? Hair. Why?
> >If we can answer that question, then maybe it will be evident why man does
> > not need all that much hair.
> Well, a long time ago I learned from hunters that snow
> stayed unmelted for hours on the backs of deer here
> in the Northeast after a snowstorm. The insulative
> properties of hair must be high.
> Could it be that hair insulates internal organs from cold AND hot climates?
> Doug McKean

Doug, I don't know if you ment this or I am interpreting you incorrectly.
Is this your thesis: That the insulative properties of hair (on zebras,
lions,etc) actually serves to keep the heat in, not out?

This is a real turn of the tables. I think all I have read on the subject
assumes that the animal's metabolism is pretty much too strong for his own
good and so he grows hair to cool off and keep out additional heat from
the sun. But this is a waste of good metabolism. Let us say the ideal
operating temperature is 98 degrees. In your view it would be much more
efficient to have a natural metabolism running at, say, 90 degrees and
then grow a layer of hair that through insulation raised it up to the
ideal. Much less wasted energy.

I wonder if this could be tested? If you shaved a zebra could you measure
the increase in metabolism needed to keep his temperature at the ideal

And getting back to the original question, I wonder what, if true, the
implications would be for man losing his hair?

Thanks for a very interesting idea