The Rational Optimist: How Prosperity Evolves. Matt Ridley
armadillos, too; while Hadza women in Tanzania collect tubers, fruit and nuts, men hunt antelope; while Greenland Inuit men hunt seals, women make stews, tools and clothing from the animals. And so on, through example after example. Even the apparent exceptions to the rule, where women do hunt, are instructive, because there is still a division of labour. Agta women in the Philippines hunt with dogs; men hunt with bows. Martu women in western Australia hunt goanna lizards; men hunt bustards and kangaroos. As one anthropologist put it after living with the Khoisan, ‘Women demand meat as their social right, and they get it – otherwise they leave their husbands, marry elsewhere or make love to other men.’
What is true of extant hunter-gatherers was equally true of extinct ways of life, as far as can be ascertained. Cree Indian women hunted hares; men hunted moose. Chumash women in California gathered shellfish; men harpooned sea lions. Yahgan Indians (in Tierra del Fuego) hunted otters and sea lions; women fished. In the Mersey estuary near Liverpool are preserved dozens of 8,000-year-old footprints: the women and children appear to have been collecting razor clams and shrimps; the men’s prints are moving fast and paralleling those of red and roe deer.
An evolutionary bargain seems to have been struck: in exchange for sexual exclusivity, the man brings meat and protects the fire from thieves and bullies; in exchange for help rearing the children, the woman brings veg and does much of the cooking. This may explain why human beings are the only great apes with long pair bonds.
Just to be clear, this argument has nothing to do with the notion that ‘a woman’s place is in the home’ while men go out to work. Women work hard in hunter-gatherer societies, often harder than men. Neither gathering nor hunting is especially good evolutionary preparation for sitting at a desk answering the telephone. Anthropologists used to argue that the sexual division of labour came about because of the long, helpless childhood of human beings. Because women could not abandon their babies, they could not hunt game, so they stayed near the home and gathered and cooked food of the kind that was compatible with caring for children. With a baby strapped to your back and a toddler giggling at your feet, it is undoubtedly easier to gather fruit and dig roots than it is to ambush an antelope. The anthropologists have been revising the view that the division of labour by sex is all about childcare constraints, though. They have found that even when hunter-gatherer women do not face a hard choice between child care and hunting, they still seek out different kinds of food from their menfolk. In the Alyawarre aborigines of Australia, while young women care for children, older women go out looking for goanna lizards, not for the kangaroos and emus that their menfolk hunt. A sexual division of labour would exist even without childcare constraints.
When did this specialisation begin? There is a neat economic explanation for the sexual division of labour in hunter-gatherers. In terms of nutrition, women generally collect dependable, staple carbohydrates whereas men fetch precious protein. Combine the two – predictable calories from women and occasional protein from men – and you get the best of both worlds. At the cost of some extra work, women get to eat some good protein without having to chase it; men get to know where the next meal is coming from if they fail to kill a deer. That very fact makes it easier for them to spend more time chasing deer and so makes it more likely they will catch one. Everybody gains – gains from trade. It is as if the species now has two brains and two stores of knowledge instead of one – a brain that learns about hunting and a brain that learns about gathering.
Neat, as I say. There are untidy complications to the story, including that men seem to strive to catch big game to feed the whole band – in exchange for both status and the occasional seduction – while women feed the family. This can lead to men being economically less productive than they might be. Hadza men spend weeks trying to catch a huge eland antelope when they could be snaring a spring-hare each day instead; men on the island of Mer in the Torres Strait stand with spears at the fringe of the reef hoping to harpoon giant trevally while their women gather twice as much food by collecting shellfish. Yet even allowing for such conspicuous generosity or social parasitism – depends on how you view it – the economic benefits of food sharing and specialised sex roles are real. They are also unique to human beings. There are a few birds in which the sexes have slightly different feeding habits – in the extinct Huia of New Zealand male and female even had different beak shapes – but collecting different foods and sharing them is something no other species does. It is a habit that put an end to self-sufficiency long ago and that got our ancestors into the habit of exchange.
When was the sexual division of labour invented? The cooking theory points to half a million years ago or much more, but two archaeologists argue otherwise. Steven Kuhn and Mary Stiner think that modern, African-origin Homo sapiens had a sexual division of labour and Neanderthals did not, and that this was the former’s crucial ecological advantage over the latter when they came head-to-head in Eurasia 40,000 years ago. In advancing this notion they are contradicting a long-held tenet of their science, first advocated by Glyn Isaac in 1978 – that different sex roles started with food sharing millions of years ago. They point out that there is just no sign of the kind of food normally brought by gatherer women in Neanderthal debris, nor of the elaborate clothing and shelters that Inuit women make while their men are hunting. There are occasional shellfish, tortoises, eggshells and the like – foods easily picked up while hunting – but no grindstones and no sign of nuts and roots. This is not to deny that Neanderthals cooperated, and cooked. But it is to challenge the notion that the sexes had different foraging strategies and swapped the results. Either the Neanderthal women sat around doing nothing, or, since they were as butch as most modern men, they went out hunting with the men. That seems more likely.
This is a startling shift of view. Instead of talking about ‘hunter-gathering’ as the natural state of humanity effectively since forever, as they are apt to do, scientists must begin to consider the possibility that it is a comparatively recent phase, an innovation of the last 200,000 years or so. Is the sexual division of labour a possible explanation of what made a small race of Africans so much better at surviving in a time of megadroughts and volatile climate change than all other hominids on the planet?
Perhaps. Remember how few are the remains from Neanderthal sites. But at least the burden of proof has shifted a bit. Even if the habit is more ancient, it may have been the predisposing factor that then conditioned the African race to the whole notion of specialisation and exchange. Having trained themselves to specialise and exchange between the sexes, having got into the habit of exchanging labour with others, the thoroughly modern Africans had then begun to extend the idea a little bit further and tentatively try a new and still more portentous trick, of specialising within the band and then between bands. This latter step was very hard to take, because of the homicidal relationships between tribes. Famously, no other species of ape can encounter strangers without trying to kill them, and the instinct still lurks in the human breast. But by 82,000 years ago, human beings had overcome this problem sufficiently to be able to pass Nassarius shells hand to hand 125 miles inland. Barter had begun.
Beachcombing east
Barter was the trick that changed the world. To paraphrase H.G. Wells, ‘We had struck our camp forever, and were out upon the roads.’ Having conquered much of Africa by about 80,000 years ago, the modern people did not stop there. Genes tell an almost incredible story. The pattern of variation in the DNA of both mitochondrial and Y chromosomes in all people of non-African origin attests that some time around 65,000 years ago, or not much later, a group of people, numbering just a few hundred in all, left Africa. They probably crossed the narrow southern end of the Red Sea, a channel much narrower then than it is now. They then spread along the south coast of Arabia, hopping