The !Kung bushmen of Africa, romanticized in the 1930s by Elisabeth Marshall Thomas as “the harmless people”, had a yearly murder rate of 40 per 100,000, which declined by more than 30 per cent once they became subject to state authority. This is a very instructive example of complex social structures serving to reduce, not exacerbate, the violent tendencies of human beings. Yearly rates of 300 deaths per 100,000 have been reported for the Yanomami of Brazil, famed for their aggression, but the stats don’t max out in the Amazon. Closer to home, the people of Papua New Guinea kill each other at yearly rates variously ranging from 140 to 1000 per 100,000. However, the bloodiest record appears to be that of the Kato, an indigenous people of California, 1450 of whom per 100,000 met violent deaths in the 1840s, as Lawrence H. Keeley notes in War Before Civilization: The myth of the peaceful savage. As the publisher’s blurb puts it:

… To support this point, Keeley provides a wide-ranging look at warfare and brutality in the prehistoric world. He reveals, for instance, that prehistorical tactics favoring raids and ambushes, as opposed to formal battles, often yielded a high death-rate; that adult males falling into the hands of their enemies were almost universally killed; and that surprise raids seldom spared even women and children.

Keeley cites evidence of ancient massacres in many areas of the world, including the discovery in South Dakota of a prehistoric mass grave containing the remains of over 500 scalped and mutilated men, women, and children — a slaughter that took place a century and a half before the arrival of Columbus….

In defense of this thesis, Keeley devotes most of his well-written book to discussion and documentation of several aspects of pre-contact native warfare, some of which he judges as superior to modern battle, including weapons, tactics (more frequent encounters and raids rather than fewer but prolonged actions), forms of combat (small ambushes and larger raids on settlements preferred), and casualties (much deadlier than modern war in terms of deaths relative to total population). The author also considers the material gains and losses of native war, especially the high logistical vulnerability of small-scale societies to looting and destruction.