Re: Bipedalism and speculation (was bipedalism and theorizing... was Re: Morgan and creationists
Sun, 15 Sep 1996 18:33:52 GMT (Paul Crowley) wrote:

(in response to a post by JohnWaters)

>You're saying (a) proto-hominids got smaller (b) their brains
>got relatively larger, (c) this lead to more altricial infants
>which (d) caused bipedalism.

>I find this, in itself, a bit hard to accept. You're saying that
>smaller mothers with more slowly developing infants would have a
>significant advantage over larger females with faster developers.

On the face of
>it, an infant with an altricial period of one week would have a
>much smaller chance of survival than one with a period of a day.
>You need to be able to specify some very substantial compensatory

Which brings up the significance of expanding crania. It appears that
the benefits of having large headed offspring (however helpless) must
have outweighed the risks. One of the risks I see little mention of
around here is to the mother in trying to give birth to such
offspring. Ouch!!!

There is some evidence that the pelvic opening of female
h.s.neandertal was relatively small compared to extant homo sapien
females. We know that the average size of the neandertal brain case
is larger than that of the average extant homo sapien. If the
neandertal infant is anything like todays' homo sapien infants...and I
honestly do not know about that, but if they were, it makes one ponder
the infant mortality rate in neandertal, not to mention the survival
of the mother!