Friday, October 30, 2009

Sex and war

In the same issue of Science as Kaplan's review of Sex and War, there is a News/Focus article on the evolutionary history of Neanderthals and Homo sapiens.

The standard view has been that Neanderthals and modern humans shared a common ancestor, most likely in Africa, something less that 500,000 years ago. The population that became the Neanderthals was first to migrate into Europe and western Asia a few hundred thousand years ago, where they lived unmolested until H. Sapiens appeared on the scene about 40,000 years ago. The two species of humans lived side by side for 10,000 years until the Neanderthals were driven into a final refuge -- southern Spain -- where they became extinct. The evidence seems to suggest an unharmonious relationship between Neanderthals and H. Sapiens, an early chapter, perhaps, of sex and war.

Recent fossil finds have complicated the picture. Some anthropologists now believe that two or more hominid species might have lived in Europe and western Asia before H. sapiens came sweeping out of Africa. More sex and war, no doubt, more competition for resources, more chances to practice the fine art of killing. In these earlier hypothesized encounters, Neanderthals came out on top, driving the other populations to extinction, only to be vanquished in turn by our own immediate ancestors.

The image above from Science (credit: Mauricio Anton) reconstructs the species of hominids represented by a trove of half-million-year-old fossils found at Sima de los Huesos in northern Spain. They aren't us, but they aren't all that not-us either. In the drawing, they look rather like they are posing for a group photo at a family reunion. Did they have language? Religion? Did they bury their dead? Did they sing and dance? We have lots left to learn. In any case, once H. sapiens moved into their territory, they were soon gone.

War? Likely. Rape? Mate capture? As far as I know, there is no widely-accepted evidence of interbreeding between H. sapiens and their Euro-Asian predecessors, although the complete sequencing of Neanderthal DNA may yet have more to tell us.

I keep coming back to that haunting drawing of the Sima de los Huesos humans. Modern humans don't have to learn sex and war; it would appear to be in our genes, and probably in their genes too. Learning to love the other is rather more problematic.