Re: Bipedalism and theorizing... was Re: Morgan and creationists

Ralph L Holloway (
Thu, 11 Jul 1996 16:37:56 -0400

On Thu, 11 Jul 1996, Gerrit Hanenburg wrote:

> I've looked up some species averages for life-history variables.
> -neonatal bodyweight:
> Homo sapiens-3300.0 g.
> Pan troglodytes-1756.0 g.
> -neonatal brainweight:
> H.sapiens-384.0 g.
> P.troglodytes-128.0 g.
> Ratio neonatal brainweight/neonatal bodyweight:
> H.sapiens-11.6%
> P.troglodytes-7.3%
> In my opinion these differences alone pose a different nutricional
> demand in that H.sapiens neonates need a higher daily caloric intake.
> This difference becomes even greater if we take into account the fact
> that a human infant has a far higher rate of braingrowth in the first
> year of life (almost tripling it's brainsize)
> Given that the infant subsists almost entirely on mother's milk during
> the first year of life,I thought that the caloric output of the human
> breast must be greater than in chimpanzees and that one way of solving
> the problem would be an increase in the amount of glandular tissue.
> This could explain part of the difference in breastsize between humans
> and apes.
> (Source of neonatal body- and brainweight:Harvey,P.H.,Martin,R.D.and
> Clutton-Brock,T.H.(1987),Life Histories in Comparative
> Perspective.p.185 in Smuts, al.(1987),Primate
> Societies,University of Chicago Press)

The logic sure makes sense to me, but I simply have no knowledge regarding
any significant differences between human and chimp in the nutritional
quality of mother's milk. Surely, somewhere in the primate literature,
there must be some reference to the the biologic constitution of
chimpnazee milk compared to that for the human. I know such profiles exist
for cow, sheep, and porcine, and human, but I can't remember similar
profiles for different primates. Anyone out there that look into this
interesting question? Surely someone at Yerkes..?
Ralph Holloway