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Re: chimps on the savanna? Nooooo.....
Alex Duncan (aduncan@mail.utexas.edu)
27 Oct 1995 15:03:27 GMT
In article <hubey.814766230@pegasus.montclair.edu> H. M. Hubey,
hubey@pegasus.montclair.edu writes:
>>Therefore, weight estimates derived from hind limb
>>parameters such as femoral midshaft diameter or femoral head articular
>>surface area should be too small when compared to estimates from other
>>methods.
>
>So you are looking for some hominid bones (or proto-hominid
>i..e from the aquatic stage) in which you'd expect to see
>lighter bones. It seems reasonable superficially, but why?
>
>Their ancestors were quadpeds. They had four appendages to support
>their bodies. Now they have two. Besides, the grasping foot didn't
>go away overnight even when they were bipedal, so why should then
>their bones (femurs) get lighter for the same duration?
Bones respond adaptively to the loads placed on them during life. Active
people have more robust skeletons than couch potatos. The expectation is
that a biped should have large hindlimb joint surface areas and more
larger shaft diameters for the hindlimb skeleton because the entire
weight of the upper body is being transmitted through the hindlimbs.
Conversely, if one is transmitting virtually no weight through the
hindlimbs, because one is standing in water all day, then hindlimb bone
diameters and joint surface areas should be reduced.
Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086
512-471-4206
aduncan@mail.utexas.edu
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