Re: is our brain part of evolution?
Stephen Barnard (firstname.lastname@example.org)
Tue, 15 Oct 1996 19:26:19 -0800
Richard Ottolini wrote:
> One hypothesis is the large brain is a heat exchanger for the
> demands of running. It brings lots of blood near the surface.
> Kind of like a dog's nose.
Very, very unlikely. The brain is an enormous consumer of energy. Head
wounds are notorious for their copious bleeding, because the brain
requires so much blood for nourishment. If you get overheated (playing
tennis on a hot day, for example), an effective way of cooling yourself
is to drape a wet towel over your head. This doesn't mean that the
purpose of the brain is as an heat exchanger. It means that the heat
that must be exchanged is disproportionately in the brain. It would be
ridiculously easy to design better heat exchangers.