However genocidal chimps do seem to evince intent and unsophisticated planning. The Kahama killings resulted from Kasakela groups proceeding directly, quickly, silently, and nervously towards or into Kahama territory, sitting in trees and listening for nearly an hour, and finally running to Kahama chimps that they detected. Chimps also share xenophobia with us; they clearly recognize members of other bands as different from, and treat them very differently from, members of their own band.
In short, of all our human hallmarks—art, spoken language, drugs, and the others—the one that has been derived most straightforwardly from animal precursors is genocide. Common chimps already carried out planned killings, extermination of neighbouring bands, wars of territorial conquest, and abduction of young nubile females. If chimps were given spears and some instruction in their use, their killings would undoubtedly begin to approach ours in efficiency. Chimpanzee behaviour suggests that a major reason for our human hallmark of group living was defence against other human groups, especially once we acquired weapons and a large enough brain to plan ambushes. If this reasoning is correct, then anthropologists' traditional emphasis on 'man the hunter' as a driving force of human evolution might be valid after all-with the difference that we ourselves, not mammoths, were our own prey and the predator that forced us into group living.
Of the two patterns of genocide commonest among humans, both have animal precedents: killing both men and women fits the common chimpanzee and wolf pattern, while killing men and sparing women fits the gorilla and lion pattern. Unprecedented even among animals, however, is a procedure adopted from 1976 to 1983 by the Argentine military, in the course of killing over 10,000 political opponents and their families, the desaparecidos. Victims included the usual men, non-pregnant women, and children down to the age of three or four years, who were often tortured before being killed. But Argentina's soldiers made a unique contribution to animal behaviour by specializing in killing pregnant women, who were arrested, kept alive until they delivered, and then shot in the head, so that the newborn infant could be adopted by childless military parents. If we are not unique among animals in our own propensity for murder, might our propensities nevertheless be a pathological fruit of modern civilization? Modern writers, disgusted by destruction of 'primitive' societies by 'advanced' societies, tend to idealize the former as noble savages who supposedly are peace-loving, or who commit only isolated murders rather than massacres. Erich Fromm believed the warfare of hunter-gatherer societies to be 'characteristically unbloody'. Certainly some pre-literate peoples (Pygmies, Eskimos) seem less warlike than some others (New Guineans, Great Plains and Amazonian Indians). Even the warlike peoples—so it is claimed—practise war in a ritualized fashion and stop when only a few adversaries have been killed. But this idealization does not match my experience of the New Guinea high-landers, who are often cited as practising limited or ritualized war. While most fighting in New Guinea consisted of skirmishes leaving no or few dead, groups sometimes did succeed in massacring their neighbours. Like other peoples, New Guineans tried to drive off or kill their neighbours on occasions when they found it advantageous, safe, or a matter of survival to do so. When we consider early literate civilizations, written records testify to the frequency of genocide. The wars of the Greeks and Trojans, of Rome and Carthage, and of the Assyrians and Babylonians and Persians proceeded to a common end: the slaughter of the defeated irrespective of sex, or else the killing of the men and enslavement of the women. We all know the biblical account of how the walls of Jericho came tumbling down at the sound of Joshua's trumpets. Less often quoted is the sequel. Joshua obeyed the Lord's command to slaughter the inhabitants of Jericho as well as of Ai, Makkedeh, Libnah, Hebron, Debir, and many other cities. This was considered so ordinary that the Book of Joshua devotes only a phrase to each slaughter, as if to say, of course he killed all the inhabitants, what else would you expect? The sole account requiring elaboration is of the slaughter at Jericho itself, where Joshua did something really unusual; he spared the lives of one family (because they had helped his messengers).
We find similar episodes in accounts of the wars of the Crusaders, Pacific islanders, and many other groups. Obviously, I am not saying that slaughter of the defeated irrespective of sex has always followed crushing defeat in war. Yet either that outcome, or else milder versions hke the killing of men and enslavement of women, happened often enough that they must be considered more than a rare aberration in our view of human nature. Since 1950 there have been nearly twenty episodes of genocide, including two claiming over a million victims each (Bangladesh in 1971, Cambodia in the late 1970s) and four more with over a hundred thousand victims each (the Sudan and Indonesia in the 1960s, Burundi and Uganda in the 1970s) (see map on page 258).
Thus, genocide has been part of our human and prehuman heritage for millions of years. In light of this long history, what about our impression that twentieth-century genocide is unique? There is little doubt that Stalin and Hitler set new records for number of victims, because they enjoyed three advantages over killers of earlier centuries—denser populations of victims, improved communications for rounding up victims, and improved technology for mass killing. As another example of how technology can expedite genocide, the Solomon Islanders of Roviana Lagoon in the Southwest Pacific were famous for their headhunting raids that depopulated neighbouring islands. However, as my Roviana friends explained to me, these raids did not blossom until steel axes reached the Solomon Islands in the Nineteenth Century. Beheading a man with a stone axe is difficult, and the axe blade quickly loses its sharp edge and is tedious to resharpen. A much more controversial question is whether technology also makes genocide psychologically easier today, as Konrad Lorenz has argued. His reasoning goes as follows. As humans evolved from apes, we depended increasingly for our food on killing animals. However, we also lived in societies of more and more individuals, between whom cooperation was essential. Such societies could not maintain themselves unless we developed strong inhibitions about killing fellow humans. Throughout most of our evolutionary history, our weapons operated only at close quarters, so it was enough that we be inhibited from looking another person in the face and killing him/her. Modern push-button weapons bypassed these inhibitions by enabling us to kill without even seeing our victims' faces. Technology thus created the psychological prerequisites for the white-collar genocides of Auschwitz and Treblinka, of Hiroshima and Dresden. I am uncertain whether this psychological argument really contributed significantly to the modern ease of genocide. The past frequency of genocide seems to have been at least as high as today's, though practical considerations limited the number of victims. To understand genocide further, we must leave dates and numbers and inquire about the ethics of killing.