Re: Brain Temperature Control & A. Africanus

Doug McKean (
Mon, 28 Oct 1996 18:20:10 -0500

Gerrit Hanenburg wrote:
> I wouldn't say that it was the driving factor but only one of the
> factors that made increased encephalization possible.
> The system of emissary veins may have been necessary from the point of
> view of thermoregulation,in my opinion it does not explain the
> selective advantage of a big brain.

Yes. Understood. Rescind "driving". Too strong.
Nor does it explain a coordinated and simultaneous
growth of the bone material to accommodate the larger brain.
The explanations I've read follow your point rather than brain growth.
They can be used to explain an increase in emissary veins for thermoregulation,
but that in and of itself does not explain a bigger brain.

IMO (just unsubstantiated hypothesizing now), some enviromental stimulae
sparked the need for increased brain size to survive (maybe that's too obvious)
but after the stimulae disappeared or adaption to it succeeded,
what remained was a continued increase in brain growth.

Doug McKean
The comments and opinions stated herein are mine alone,
and do not reflect those of my employer.