Sunday 11 August 2002

Pic of the day: A decent attempt to implement steatopygia in a RPG - screenshot from Daggerfall. (Sadly there is no such thing in the sequel, Morrowind. On the other hand, you have catgirls with realistically swishing tails. Not quite the same.)

Steatopygia

You would expect this to be an uncontroversial topic. Steatopygia is an ancient Greek word meaning "fat rump", and refers to an inherited condition in which large amounts of fat accumulate on the buttocks. The word is steadily gaining acceptance as a description of fat backsides in general, but in the scientific community it refers to a special and unusual condition in which large amounts of firm fatty tissue stands out, shelf-like, for several inches at the top of the buttocks (which are also enlarged overall). The shape is such that it has been guessed that maybe babies were supposed to sit there – you could literally place things on top of their behinds and not have them fall off, like a shelf. No kidding. This true steatopygia is known only in a few small ethnic groups. And this, of course, is where the controversy comes in. Particularly since the ethnic groups are mostly African.

The reason why I came to think of this today, was yet another idea for a fantasy novel. Actually a fantasy novel in science fiction disguise. I wanted my character to be transported to a parallel world, but not completely parallel. Over the years I have used various means to keep worlds unique while still rendering the population human. So I thought to myself: Why not a world where steatopygia is the norm? After all, it could have happened. The question is rather why it didn't.

***

As far as I knew this afternoon, steatopygia had been observed only in two ethnic groups in modern times, both of them in southern Africa, and one of them now extinct (or rather assimilated into the black African population around them). The remaining group is the !kung or "Bushmen", a small ethnic group that was widespread in southern Africa before the coming of both the white and the black. In genetic terms, they may be the most unique in the world, even more so than the Australian Aborigines.

Figurines from the last ice age depict some women who also seem to have this condition. Based on this, some researchers have believed that steatopygia was the original human condition. For women, that is. In the extreme form found in the Khoisan peoples ("bushmen" and "hottentots"), it is clearly gender-defined. While men of this "race" may have slightly larger buttocks than the average, compared to overall body size, the difference between men and women in this area is markedly greater than among the British, whom God created in his image (or at least who created the encyclopaedia). I probably don't need to mention that the men of these people also have another adaptation... No, I don't think I need to go into that much detail. Fast forward.

My deceptively simple worldview was like this: Humans originated in Africa, and were originally similar to the Khoisan people. They spread throughout Africa and then spilled over into the rest of the world. After a while, they changed, and one of the changes was the reduction of the fat deposits to a more manageable level. Perhaps the very process of migration that spread humans over the world made them more mobile. Having a significant part of your body mass standing straight out behind you does nothing good for mobility, I assume. Not that I have tried.

The wandering tribes then, over something like 70 000 years, grew into the various "races" that we see today. Being so widely dispersed and separated caused the great variation we find in modern humans, despite the close genetic kinship between us. (The genetic diversity in humans is so low that if it were found in another mammal species, it would be taken as a sign of inbreeding and a risk to the future of the species. Among most apes, you can find that much variation within a family.) Oh, and ... this is kinda explosive if you didn't know it: The current black Africans, "Negroes" as we used to call them when I was young, are not native to the continent. They came during the last few thousand years, from the east, in several waves. The Europeans reached the south coast of Africa before the blacks did, though not by many years. The two between them enslaved and slaughtered the native Khoisan population with equal ferocity. Besides the Khoisan, the pygmies (whose politically correct name I have forgotten) are also widely recognized as indigenous to the continent.

***

My wandering on the Web found a lot of resistance to the idea that Paleolithic carvings displayed steatopygia. I actually now think they don't. Most likely they just show women with big butts (and more often than not also swollen breasts and wombs). The shelf-type steatopygia may have already been gone by then, replaced by our more rounded version of enlarged seat, which is still found in individuals and families of a wide range of ethnic groups. Or perhaps it never left Africa ... but there is a reason to think it did. A small group of "Negritoes" on islands west of Indonesia have practically the same condition, or at least more pronounced than other people outside Khoisan and Pygmy.

One reason why steatopygia got lost fairly early may have been the cold. This all took place during the ice age, and having your fat distributed all over your body made a lot more sense. In a hot desert, such as the Kalahari where the !kung people now live, it makes sense to gather it all in one place. The choice of exactly where may have been a case of sexual selection, as Charles Darwin believed.

I am amazed by the vehemence with which some people deny that the difference between African groups is larger than between other "races". One even claimed that steatopygia is common to most black women, which it plainly is not. So what if most blacks are not aboriginal to Africa? Does it matter? Most Americans are certainly not aboriginal to America. The modern European is comparatively a latecomer to the continent, leaving scattered enclaves of older peoples in the Basque territories and (somewhat diluted) in parts of Norway. The Jews that returned to Israel were not the ones who left, genetically speaking. People moving around has been the norm on this planet. We are a wandering species. The loss of shelf-like steatopygia is just one more proof of that.