The Red Queen_ Sex and the Evolution of Human Nature - Matt Ridley [93]
Hunters or Gatherers
The lesson for humanity is obvious. To determine our mating system, we need to know our natural habitat and our past. Mankind has lived mostly in cities for less than one thousand years. He has been agricultural for less than ten thousand. These are mere eyeblinks. For more than a million years before that he was recognizably human and living, mostly in Africa, probably as a hunter-gatherer, or forager, as anthropologists now prefer to say. So, inside the skull of a modern city dweller there resides a brain designed for hunting and gathering in small groups on the African savannah. Whatever humanity’s mating system was then is what is ‘natural’ for him now.
Robert Foley is an anthropologist at Cambridge University who has tried to piece together the history of mankind’s social system. He starts with the fact that all apes share the habit of females leaving their natal group, whereas all baboons share the habit of males leaving their natal group. It seems to be fairly hard for a species to switch from female exogamy to male exogamy or vice versa. On average, human beings are typical apes, in this respect, even today. In most societies, women travel to live with their husbands, whereas men tend to remain close to their relatives. There are some exceptions, though: in many, but not most traditional human societies, men move to women.
Female exogamy means that apes are largely devoid of mechanisms for females to build coalitions of relatives. A young female chimpanzee generally must leave her mother’s group and join a strange group dominated by unfamiliar males. To do so she must worm her way into the favour of the females that already live in her new tribe. A male, by contrast, stays with his group and allies himself to powerful relatives in the hope of inheriting their status later.
So much for the the ape’s legacy to mankind. What about the habitat in which he lived? Towards the end of the Miocene era, some twenty-five million years ago, Africa’s forests began to contract. Drier, more seasonal habitats – grasslands, scrublands, savannahs – began to spread. About seven million years ago, the ancestors of mankind began to diverge from the ancestors of modern chimpanzees. Even more than chimpanzees, and much more than gorillas, mankind’s ancestors moved into these new dry habitats and gradually adapted to them. We know this because the earliest fossils of man-like apes (the australopithecines) were living in places that at the time were not covered by forest: at Hadar in Ethiopia and Olduvai in Tanzania. Presumably, these relatively open habitats favoured larger groups as they did for chimps and baboons, the two other open-country primates. As socioecologists find again and again, the more open the habitat, the bigger the group, both because big groups can be more vigilant in spotting predators and because the food is usually found in a more patchy pattern. For reasons that are not especially persuasive (principally the apparently great size difference of males and females), most anthropologists believe the early australopithecines lived in single-male harems, like gorillas and some species of baboon.24
But then, some time around three million years ago, man’s lineage split in two (or more). Robert Foley believes the increasingly seasonal pattern of rainfall had made the lifestyle of the original ape-man untenable, for its diet of fruit, seeds and perhaps insects became