There may be several reasons at work. Scholars tend to like, to identify with, or to sympathize with the traditional people among whom they live for several years. The scholars consider war bad, know that most readers of their monographs will also consider war bad, and don’t want “their” people to be viewed as bad. Another reason involves unfounded claims (to be discussed below) that human warfare has an inexorable genetic basis. That leads to the false assumption that war would be unstoppable, and hence to a reluctance to acknowledge the apparently depressing conclusion that war traditionally really has been widespread. Still another reason is that some state or colonial governments are eager to get indigenous people out of the way by conquering or dispossessing them or by turning a blind eye to their extermination. Branding them as warlike is used as an excuse to justify that mistreatment, so scholars seek to remove that excuse by trying to absolve the indigenous people of the charge of being warlike.
I sympathize with scholars outraged by the mistreatment of indigenous peoples. But denying the reality of traditional warfare because of political misuse of its reality is a bad strategy, for the same reason that denying any other reality for any other laudable political goal is a bad strategy. The reason not to mistreat indigenous people is not that they are falsely accused of being warlike, but that it’s unjust to mistreat them. The facts about traditional warfare, just like the facts about any other controversial phenomenon that can be observed and studied, are likely eventually to come out. When they do come out, if scholars have been denying traditional warfare’s reality for laudable political reasons, the discovery of the facts will undermine the laudable political goals. The rights of indigenous people should be asserted on moral grounds, not by making untrue claims susceptible to refutation.
Warlike animals, peaceful peoples
If one defines war as I defined it on p. 131—“recurrent violence between groups belonging to rival political units, and sanctioned by the units”—and if one takes a broadened view of “political units” and “sanctioned,” then war characterizes not only humans but also some animal species. The species most often mentioned in discussions of human war is the common chimpanzee, because it is one of our two closest living animal relatives. War among chimpanzees resembles human band and tribal warfare in consisting of either chance encounters or else apparently intentional raids involving adult males. Calculated war-related death rates in chimpanzees, 0.36% per year (i.e., 36 chimpanzees per year in a population of 10,000), are similar to those for traditional human societies. Does this mean that warfare was transmitted to humans in a straight line from our chimpanzee ancestors, hence that it has a genetic basis, hence that we are helplessly pre-programmed to make war, hence that it’s inevitable and can’t be prevented?
The answer to all four of these questions is no. Chimpanzees are not the ancestors of humans; instead, chimpanzees and humans are both descended from a common ancestor that lived about 6,000,000 years ago, and from which modern chimpanzees may be more divergent than are modern humans. It is not the case that all descendants of that common ancestor make war: bonobos (formerly known as pygmy chimpanzees), which genetically are the same distance from us as are chimpanzees and hence are the other one of our two closest animal relatives, are also derived from that common ancestor but have not been observed to make war; and some traditional human societies don’t make war. Among social animal species other than chimpanzees, some (e.g., lions, wolves, hyenas, and some ant species) are known to practise lethal fighting between groups, while others are not known to do so. Evidently, war does arise repeatedly and independently but is not inevitable among social animals in general, nor within the human-chimpanzee evolutionary line in particular, nor among modern human societies more particularly. Richard Wrangham argues that two features distinguish those social species that do practise war from those that don’t: intense resource competition, and occurrence in groups of variable size such that large groups sometimes encounter small groups or individual animals which they can safely attack and overwhelm by numbers with little risk to the aggressors.
As for a genetic basis to human warfare, it of course has a genetic basis, in the same broad and distant sense in which cooperation and other multi-faceted human behaviors have a genetic basis. That is, the human brain and hormones and instincts are laid down ultimately by genes, such as the genes that control the synthesis of the hormone testosterone associated with aggressive behavior. However, the normal range of aggressive behavior, like the normal range of body height, is influenced by many different genes and by environmental and social factors (like effects of childhood nutrition on adult height). That’s unlike single-gene traits such as sickle-cell hemoglobin, which a person carrying the gene for that trait synthesizes regardless of childhood nutrition, other genes, or environmental competition. Like warfare, warfare’s converse of cooperation is widespread but variably expressed among human societies. We already saw in Chapter 1 that cooperation between neighboring human societies is favored by certain environmental conditions, such as resource fluctuations within or between years, and whether or not a territory contains all resources necessary for self-sufficient survival. It is not inevitable or genetically programmed that neighboring small-scale societies cooperate; there are reasons why some cooperate more and some cooperate less.
Similarly, there are external reasons why some human societies are peaceful, although most are not. Most modern state societies have been involved in recent wars, but a few haven’t, for understandable reasons. The Central American nation of Costa Rica hasn’t had a recent war, and even abolished its army in 1949, because its historical population and social conditions resulted in relatively egalitarian and democratic traditions, and its only neighbors (Nicaragua and Panama) are unthreatening and offer no targets of great value to conquer except the Panama Canal, which would be defended by the U.S. Army if Costa Rica were foolish enough to invest in an army to attack the canal. Sweden and Switzerland haven’t had recent wars (although Sweden formerly did), because they now do have aggressive and far more powerful and populous neighbors (Germany, France, and Russia) which they could never hope to conquer themselves, and because they have successfully deterred those neighbors from attacking them by being armed to the teeth.
Like these modern states without recent involvement in wars, a small minority of traditional societies have also been peaceful for understandable reasons. Greenland’s Polar Eskimos were so isolated that they had no neighbors, no outside contacts, and no possibility of war even if they had wanted it. Absence of war has been reported for quite a few small bands of nomadic hunter-gatherers living at very low population densities, in harsh unproductive environments, with large home ranges, with few or no possessions worth defending or acquiring, and relatively isolated from other such bands. These include the Shoshone Indians of the U.S. Great Basin, Bolivia’s Siriono Indians, some Australian desert tribes, and the Nganasan of northern Siberia. Farmers without a history of war include Peru’s Machiguenga Indians, living in a marginal forest environment not coveted by others, without pockets of good land sufficiently dense or dependable to warrant war or defense, and with currently low population density, possibly because of a recent population crash during the rubber boom.