How Peaceful are Hunter-Gatherers?

The Economist looks at hunter-gatherers:

In 2006 two Indian fishermen, in a drunken sleep aboard their little boat, drifted over the reef and fetched up on the shore of North Sentinel Island. They were promptly killed by the inhabitants. Their bodies are still there: the helicopter that went to collect them was driven away by a hail of arrows and spears. The Sentinelese do not welcome trespassers. Only very occasionally have they been lured down to the beach of their tiny island home by gifts of coconuts and only once or twice have they taken these gifts without sending a shower of arrows in return.

Several archaeologists and anthropologists now argue that violence was much more pervasive in hunter-gatherer society than in more recent eras. From the
!Kung in the Kalahari to the Inuit in the Arctic and the aborigines in Australia, two-thirds of modern hunter-gatherers are in a state of almost constant tribal warfare, and nearly 90% go to war at least once a year. War is a big word for dawn raids, skirmishes and lots of posturing, but death rates are high—usually around 25-30% of adult males die from homicide. The warfare death rate of 0.5% of the population per year that Lawrence Keeley of the University of Illinois calculates as typical of hunter-gatherer societies would equate to 2 billion people dying during the 20th century.

At first, anthropologists were inclined to think this a modern pathology. But it is increasingly looking as if it is the natural state. Richard Wrangham of Harvard University says that chimpanzees and human beings are the only animals in which males engage in co-operative and systematic homicidal raids. The death rate is similar in the two species. Steven LeBlanc, also of Harvard, says Rousseauian wishful thinking has led academics to overlook evidence of constant violence.