Re: Bipedalism and theorizing... was Re: Morgan and creationists
Gerrit Hanenburg (ghanenbu@inter.nl.net)
Tue, 1 Oct 1996 19:42:18 GMT
"John Waters" <jdwaters@dircon.co.uk> wrote:
>>The infant is an eccentric weight.So,twisting the body slightly to the
>>opposite side would result in the projection of the center of
>>gravity within the supporting surface formed by the feet,like we do
>>when carrying a bag in one hand or a child on the hip.
>>That is a requisite for maintaining balance,but long distance
>>walking requires more than just that.
>JW: This is very interesting. Are you saying that a chimpanzee
>(like Faben) with a paralysed arm could walk long distances,
>but that a nursing female with a new born infant could not?
>What are the extra requirements that such a female would need?
Jane Goodall:"Chimpanzees walk upright for a few yards when their arms
are full of fruit or when peering over long grass,but Faben can
maintain this stride for about thirty yards at a stretch."
(National Geographic (1979) vol.155 nr.5,p.607)
I hesitate to call thirty yards long distance,but I guess that when
Faben can do it,then a female chimp with an infant can do it
too,although you must realize that the infant is an *extra* eccentric
weight unlike Faben's arm.
What I meant was that regular "genuine" long distance walking (say 200
yards or more) requires a reorganization of the pelvic region and
lower limbs.
As you probably know,when chimps stand or walk bipedally,they do so
with flexed hips and knees in order to retain maximum lever advantage
for the hamstring muscles.This requires a lot of energy and leads to
rapid fatigue.
To change that,any chimp that aspires to become a long-distance
bipedalist should at least do the following:
-extend the lower limb.
-increase the angle between ilium and ischium.
-develop a lumbar lordosis.
Gerrit
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