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Re: An alternative to ST and AAT
John Waters (jdwaters@dircon.co.uk)
4 Nov 1996 00:41:40 GMT
Paul Crowley <Paul@crowleyp.demon.co.uk> wrote in article
<847016246snz@crowleyp.demon.co.uk>...
> In article <327A0E11.7012@scn.org> bh162@scn.org "Phillip
Bigelow" writes:
>
> > So, bipedalism in the kangaroo rat (Rodentia) shouldn't
have happened
> > either, right? So, bipedalism in non-avian theropods
> > (Dinosauria) shouldn't have happened, right? So,
bipedalism shouldn't
> > have happened in all birds (Dinosauria: Theropoda:
Aves), right?
> > So, bipedalism shouldn't have happened in kangaroos
(Marsupalia),
> > right?
>
> Everything in this list shares a common feature: the
females
> are not handicapped by young holding onto their bodies
while
> they progress along the ground. Most leave them in
nests, and
> the kangaroos have a special pouch. Whereas nearly all
primate
> females carry large infants on their bellies or,
sometimes, on
> their backs; this prevents them adopting an upright
posture
> when travelling on the ground.
JW: Human primate females carry their infants in their arms
or
on their hips. Nothing prevents them from maintaining an
upright posture when travelling on the ground. Furthermore,
in Jane Goodhall's _The Chimpanzees of Gombe_ Jane relates
the case of Madam Bee, a nursing female who lost the use of
one arm through polio. This female learned to walk
bipedally,
holding her infant with the remaining good arm.
Surely, if a quadrupedally adapted specie like a chimpanzee
could walk bipedally with an infant, a non quadrupedally
adapted ape could manage the same feat? (Hominid
fossils show no sign of quadrupedal adaptations.)
John.
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