Re: Austrailia

Andreas L. Opdahl (
28 Sep 1995 15:01:18 +0100

In article <449g9r$8od@jupiter.WichitaKS.HMPD.COM>, (Jim Foley) writes:
|> In article <>, Ralph L Holloway <> wrote:
|> >
|> >Whoa. It's pretty rare that female Australian Aboriginal brain
|> >endocasts get lower than about 900 ml, but it is true that on the
|> >average, Australian Aboriginal brain weights are somewhat lower than,
|> >say, Caucasian or Asian, at least from the data I've looked at.
|> Any references on these low brain weights? How many of them get below
|> 900, or 800 cc, say? What about male brains? Are they also low, or
|> closer to the modern norm?

Just a speculation: I think I remember having read that Inuits and/or
Eskimos have larger brains than Caucasians/Asians on average. Could this
be related to climate? As the volume/surface ratio grows with increasing
size for sphere-like objects, people living in warm climates would be
subject to selective pressure for miniaturising their neural equipment in
order to dispose of excess body heat. People in cold climates would
experience opposite pressure in order to retain heat. (Note that this
does not necessarily imply any reduction/increase in number of neurons or
synapses or their efficiency.) The argument assumes that energy consumption
(and thus heat generation) is unaffected by neural size. In case larger
neurons generates more heat, this could add to selective pressure.

Hmm - perhaps this is trivial. Just a thought... :-)


Dr. Andreas L. Opdahl, Assoc. Professor, Department of Infor-
mation Science, University of Bergen, N-5020 Bergen, NORWAY;; phone: (+47) 55
58 41 15; fax: (+47) 55 58 41 07; mailto: