Re: ....... BUTTOCKS......
J E Hawcroft (J.E.Hawcroft@shef.ac.uk)
Tue, 10 Sep 1996 15:07:44 +0100
E.G. Land wrote:
> In article <email@example.com>,
> E.G. Land <firstname.lastname@example.org> wrote:
> > Your thoughts please...
> To store fat, or to sit on? Among certain Asian groups, sitting
> on the "hunches" is more common than sitting on the buttocks. And
> chimps sit quite comfortably with no real rumps at all. Finally,
> why the divergent form and size among racial groups?
> EG Land
> BARD (aka Ed Garth Land)
> Fly On-The-Wall, Inc.
My thoughts: primates who sit on their bums in trees a lot usually have
tough-skinned pads there for the purpose, called ischial callosites.
Humans don't have them, probably because humans are not arboreal and
don't spend a lot of time sitting on tree-bark. It's true that in many
human societies squatting on the haunches is more common than sitting on
the buttocks, ie the skin and fat that covers the gluteal muscles.
It's also likely that neanderthals squatted more than they sat. When one
sits on the buttocks one's weight is on the ischial tuberosity of the
pelvis, which is a bar rather than a platform of bone. Perhaps this is
why there's so much fat deposition in this area, to cushion that bar.
It's also probable that fat deposits readily over the buttocks because
it's a nice wide, flat, out of the way place to store it. This is the
most likely explanation in my opinion, with buttocks being originally a
fat storage area which also happen, expediently, to be comfy to sit on.
The divergent form bewteen racial groups is probably due to the
divergence in torso:femur ratio rather than anything else. African races
have proportionately longer legs than European, for example, and the
buttock shape is really determined by the shape of the gluteal muscles
which operate the femur-torso movements.