THE ROOTS OF WAR: ROUSSEAU, DARWIN AND HOBBES
All serious discussions about the role of war in human societies, and especially about its inevitability or otherwise, quickly bring us back to the question of origins. We know that organised war been the constant companion of civilisation from the start of recorded history, but that is not much more than five thousand years ago. If war is just another artifact of civilisation, then we can deal with it as easily as we have dealt with slavery and the oppression of women B which is to say: only with very great difficulty and over a long period of time, but it can theoretically be done. However, if it should turn out that warfare of a less formal but no less brutal sort extends far back into the pre-civilised and even the pre-human past, then the worrisome possibility arises that war may be an inescapable part of our genetic heritage. That would be a truly discouraging thought, but I’m afraid we do have to consider it.
Walbiri society did not emphasise militarism – there was no class of permanent or professional warriors; there was no hierarchy of military command; and groups rarely engaged in wars of conquest. . . . There was in any case little reason for all-out warfare between communities. Slavery was unknown; portable goods were few; and territory seized in a battle was virtually an embarrassment to the victors, whose spiritual ties were with other localities.
From Desert People, an anthropological study published in 1960
…we were unexpectedly intruded upon by a very numerous tribe, about three hundred. Their appearance coming across the plain, occasioned great alarm. . . . On the hostile tribe coming near, I saw they were all men. . . . In a very short time, the fight began. . . . Men and women were fighting furiously, and indiscriminately, covered with blood, two of the latter were killed in this affair. [There was a counter-attack that night] and finding most of them asleep, laying about in groups, our party rushed upon them, killing three on the spot, and wounding several others. The enemy fled. . . leaving their war implements in the hands of their assailants and their wounded to be beaten to death by boomerangs.
William Buckley, ca. 1835 
When I wrote the first edition of this book twenty years ago, I used only the first quote, which describes an Aboriginal group in Australia that was studied in the first half of the twentieth century. Every word of it is true, at least for the time when the study is done, and I used it as evidence that “real” warfare did not exist before the rise of civilisation. In fact, I wrote: “Only a generation ago the Walbiri aborigines of Australia still lived in small bands in a hunting-and-gathering economy, as the entire human race did for at least 98 percent of its history, and although every male Walbiri was a warrior, their way of fighting did not resemble what we call ‘war’. Very few people got killed; there were no leaders, no strategy, and no tactics; and only the kinship group affected by the issue at stake — most often revenge for a killing or a ritual offence committed by another group, and hardly ever territory — would take part in the fighting.” This was how anthropologists invariably talked about warfare among hunter-gatherers at the time, and the only factual amendments I would make to the passage even today would be to point out that very few people got killed at any one time, and that the ‘kinship group’ was actually the whole band — the entire tiny society in which people lived their lives.
But contrast the second quotation, taken from a book written by William Buckley, who escaped from a penal colony on the southern coast of Australia in 1803 and lived for thirty-two years as a fugitive among the Aborigines. Writing for a European audience in the mid-nineteenth century, Buckley was not going to display the sensitivities of a late twentieth-century anthropologist, and there may be some element of exaggeration in his account: three hundred is an astonishingly high total for any hunter-gatherer group, even if we allow for the fact that this encounter was taking place in relatively fertile country before encroaching settlement made it impossible for Aborigines to follow their traditional life in the more hospitable parts of Australia. But unless he was a total fantasist, the encounter he describes was bloody, merciless, and not in the least ritualistic — and it was not the only one. If I had been a member of that band of Aborigines, I would have thought that war was a very big problem. So why is it that descriptions of the first sort, and not of the second, have shaped our perceptions of the hunter-gatherer past?
In the twenty-first century we still live amid the echoes of a great debate about the nature of human nature that broke out in Europe in early modern times. The opening shot in the intellectual battle was fired by Thomas Hobbes in 1651 when he published Leviathan, an exaltation of the powerful centralized state as mankind’s only hope of safety in a world of violence and chance. He was writing just after the Thirty Years War had wrecked much of Europe and the English Civil War had devastated his own country; his purpose was to construct a defence of constituted authority, and his method was to emphasize the chaos and misery of life without it. He had no knowledge and little interest in how people really lived in the “state of nature,” but their place in his argument was to serve as a horrible example of what life would be like without the state, so he had no hesitation in describing the lot of pre-civilized man as follows: “No arts; no letters; no society; and which is worst of all, continual fear, and danger of violent death; and the life of man, solitary, poor, nasty, brutish and short.”
The man who ultimately got the upper hand in the argument, however, was Jean-Jacques Rousseau. Writing a century later, in a generation when revolutionary ideas about equality and democracy were sweeping through the European world (he died two years after the American Revolution began, and eleven years before the outbreak of the French Revolution), Rousseau chose to make the “Noble Savage” his model of how human beings had lived before kings and priests had subjugated them to an unjust and unequal order. He knew very little about real hunter-gatherers other than that they lived in freedom and equality, but those were the values he cared about. By pointing out that people who lived in little pre-state societies still possessed these virtues, he was able to argue (in his Discourse on the Origin of Inequality in 1755) that freedom and equality were the original heritage of all mankind. Rousseau wasn’t particularly concerned about what kind of wars his Noble Savages did or didn’t fight, but his idealized picture of how people lived pre-“civilization” was hugely influential with a broad audience still living under absolute monarchies. It came to be assumed that free and equal people unburdened by property or the corrupt institutions of the state would also be able to avoid the brutal wars that tormented the civilized lands. The French revolutionaries believed it, the Marxists believed it, and in the late twentieth century most Western anthropologists still believed it despite all the evidence to the contrary.
This debate about the hunter-gatherers was and remains a centrally important argument because the best evidence for the true nature of human nature will surely be found among those who are still living as everybody lived for all but the last ten thousand years. Before mass societies, farming, commerce, religion, and the state changed us in so many ways, what were human beings really like? Were we warlike or peaceful? Tyrants or democrats? Selfish or sharing? Ecologically conscious guardians of the natural environment or rapacious destroyers? So anthropology (and archaeology) have always been politically charged disciplines – and to make matters worse, there weren’t actually many hunter-gatherers left even when Hobbes and Rousseau were writing. By the time professional anthropologists appeared on the scene in the early twentieth century, there were virtually no surviving hunter-gatherer societies that had not been in contact with more complex societies for decades or generations, and none at all that still lived in the well-watered, desirable lands that had once been home to the vast majority of hunter-gatherers: all those had been lost to the farmers long before.
The evidence we do have for the way human beings used to live, therefore, is the archaeological data gathered about long-ago hunter-gatherer bands (mostly tools, weapons, and bones), written accounts of first contacts with aboriginal groups during the centuries of European expansion, and oral histories of hunter-gatherer groups taken down by early anthropologists a generation or two after contact began to change their lives, plus contemporary observations of the few groups living in very marginal lands who still preserve many elements of the original lifestyle. It could be better, but it’s vastly more than we knew about hunter-gatherers (and therefore about ourselves) a hundred years ago – and it’s mostly pretty encouraging. Rousseau beats Hobbes by about three to one.
Little hunter-gatherer bands, generally around twenty to fifty strong, operated on the basis of rough equality among the adult members, with no designated leaders and no hierarchy. When collective decisions were necessary, which was not all that often, they were usually made by discussion and consensus – and if anybody didn’t like the decision, they were free to leave and join some other band. There were almost always other bands in the vicinity who spoke the same language, more or less, and since these little groups had to marry out to avoid genetic problems, there would probably be some relative in a neighbouring group who could help you settle in to the new band if you had to move. There was a sharp division of labour between the sexes, and men had a political advantage when group decisions had to be made because they were likelier to be related to one another (it tended to be women who moved to a different group on marriage), but there was a fair degree of equality between the sexes too. So all of our pre-history – thirty thousand generations of hunter-gatherers – tells us that we are egalitarian by nature, and democratic too.
Good news, but not really surprising: even after thousands of years in the belly of Leviathan, subordinated to the autocracy and hierarchy of the great civilized states, ordinary people have continued to behave in just this way among the small circle of family and friends that is their real social environment. Whatever we may do to foreigners at state level, at the level of individual relations we generally treat one another quite well. There remains the question of why the mass societies were so different politically, at least until very recently – but let us leave that for the moment and drop the other shoe. How did Hobbes do in the amateur anthropologist stakes?
He was dead wrong about “no society”: life in the hunter-gatherer world was not solitary, but rather total immersion in a society of a few dozen people whom you had known since childhood. It has been variously compared to a non-stop encounter group and to living your entire life on the top deck of a London bus. Hobbes was technically right about the lives of hunter-gatherers being short – most modern women cannot conceive past their mid-forties because too few of their ancestors survived that long, and so there was no evolutionary selection for fertility past that age – but while they lived they were quite impressive specimens: closer to modern Europeans or North Americans in stature, thanks to their high-protein diet, than to the undernourished and stunted Europeans of Hobbes’s time. In one big thing, however, he was right: they did live in “continual fear and danger of violent death” at the hands of their fellow men.
One year later, a gang from Kasekela found their third victim. This time the target was Goliath, now well past his prime, with a bald head, very worn teeth, protruding ribs and spine. . . . He had been a well-integrated member of the Kasekela community only five years before, and now (though he had since joined the Kahama group) he was little threat to anyone. But none of that mattered to the aggressors.
It began as a border patrol. At one point . . . they spotted Goliath, apparently hiding only 25 metres away. The raiders rushed madly down the slope to their target. While Goliath screamed and the patrol hooted and displayed, he was held and beaten and kicked and lifted and dropped and bitten and jumped on. At first he tried to protect his head, but soon he gave up and lay stretched out and still. . . . They kept up the attack for 18 minutes, then turned for home. . . . Bleeding freely from his head, gashed on his back, Goliath tried to sit up but fell back shivering. He too was never seen again.
The end of a Gombe chimpanzee 
Jane Goodall’s discovery in 1973 that the chimpanzee troop she was observing in Gombe National Park in Tanzania actually waged a kind of war against neighbouring bands came as a great surprise at the time, but subsequent studies by a number of anthropologists – some chimpanzee bands have been observed for almost forty years now, with each member named and his or her behaviour recorded over lengthy periods of time – confirmed that fighting between rival groups of chimps is widespread, chronic, and very serious. There are never pitched battles involving large numbers of individuals on each side – most of the raids that end in actual fighting are distinctly one-sided ambushes – but individuals (mostly males) are frequently killed, and on occasion entire bands are wiped out one at a time. How relevant is this to human beings?
Our line of descent separated from that of the chimpanzees five or six million years ago, but about 98 percent of our genetic material is still common to the two species. Until ten or twelve thousand years ago, all of our human ancestors made their living in essentially the same way as chimps, by foraging for food in small bands of about the same size. Both humans and chimps were hunters as well as gatherers – chimps hunt monkeys regularly, and do so in coordinated groups using clearly conscious strategies – although human weapons, and perhaps human language as well, enabled us to tackle bigger game and to incorporate much more meat in our diet.
On the other hand, apart from our greater size and intelligence, there are sharp social differences between humans and chimps. Chimpanzee society is defined by acute rivalry for dominance among the males, whereas human hunter-gatherers and their proto-human ancestors have probably lived in relatively egalitarian societies with semi-permanent bonds between individual males and females and their children – families, in other words – for several million years. Hunting big game provides large amounts of meat that must be eaten before it spoils, and so human hunter-gatherers shared food, and especially meat, as a matter of course; chimpanzees also share meat, but with much greater reluctance. And of course, we have been much more successful than chimps in evolutionary terms: we now outnumber them about twenty-five thousand to one and live in every climatic zone of the planet, while they inhabit a rapidly diminishing range in Central Africa. Nevertheless, they are our closest relatives, and how they behave is relevant to our understanding of ourselves.
Chimpanzee “warfare” is hampered by the fact that they lack weapons, and it is very difficult for chimpanzees to kill each other with their bare hands. As a result, most successful raids involve a number of male chimps from one band attacking a lone chimp from another, with some holding him down while others pummel and bite him – and even then the victim is often still alive when the attackers leave, though he generally dies afterwards. But it is warfare, in the sense that it is purposeful and calculated. According to primatologist Richard Wrangel, who did his earliest work with Goodall’s team in Gombe in the early 1970s, they conduct deliberate raids and make considerable use of surprise. Nor is it just blind aggression, triggered by the proximity of a chimp from another band: these raiding parties listen and count the calls of other troops to see if they are outnumbered. In fact, they almost always withdraw rather than attack unless they can catch a single victim from a rival band on his own. Moreover, although the great majority of killings involve the ambush of single chimps separated from their group, a campaign may be waged over a period of months or years until all the males of the rival band have been annihilated. Once that is done, the territory of the defeated group may be taken over, and the surviving females may be incorporated into the victorious group – but the infants will be killed.
Two more things, both of them with worrisome echoes in human behaviour. One of them is that chimpanzee bands typically have a territory of about fourteen square miles, but spend almost all their time in only the six central square miles. The rest is equally rich in resources but they treat it as a “no-man’s land,” presumably because of the danger of ambush and death at the hands of a neighbouring troop. The other is that this endemic chimpanzee warfare, according to long-term studies of several troops, eventually causes the death of about 30 percent of males and a much lower but still significant proportion of females. 
My old friend . . . had a spear sent right through his body, and then they hunted out his wife and killed her dead upon the spot. The savages then came back to where I was supporting my wounded friend; who seeing them approaching, sprung up, even in the last agonies of death, and speared the nearest assailant in the arm. My friend was, of course, dispatched immediately, with spears and boomerangs, as was a son of his.
William Buckley 
Similar studies of human hunter-gatherers who still lived in intact societies were almost never made by direct observation; William Buckley’s account of life among Australian aborigines in the early nineteenth century is a rare exception. In the early twentieth century, however, ethnographer Lloyd Warner conducted extensive interviews among the Murngin people of Arnhem Land in northern Australia, who lived in a resource-rich territory where human population density was relatively high, and who had only recently come into regular contact with Europeans. Relying on the strong oral history tradition among preliterate peoples, he reconstructed as best he could from the interviews the scale of warfare among the Murngin of the late 1800s. The Murngin numbered around three thousand people and lived in many separate bands of the classic hunter-gatherer type. Out of a fighting-age population of about eight hundred adult males, Warner estimated that around two hundred had died in warfare over a two-decade period at the end of the nineteenth century. Twenty years is roughly the length of time that any individual male would have been regarded as an active warrior, so these figures translate into a cumulative 25 percent death rate from warfare among males. 
So how could anybody believe, as most anthropologists have done throughout the twentieth century, that warfare among hunter-gatherers was a mostly harmless ritual activity? It was possible partly because of the continuing influence of Rousseau, and partly because among the Murngin and their brethren elsewhere there were relatively few pitched battles that resembled the kind of war that dominated the anthropologists’ own societies. They did occasionally have a formal battle (including two recorded by Warner in which over a dozen men were killed), but the great majority of clashes followed the usual hunter-gatherer pattern of raids on sleeping camps or ambushes of severely outnumbered opponents. In most of these events, only a few individuals, or one, or most frequently none at all, were killed, but the clashes were so constant that over a lifetime Murngin men stood as great a chance of dying in war as the conscript soldiers of Napoleon’s France or Hitler’s Germany.
Exactly half a world away from the Murngin, anthropologist Ernest Burch launched a very similar investigation of warfare among the Eskimos of northwestern Alaska in the 1960s. Since warfare had largely ceased once contact with Europeans and Americans was established ninety years before, he drew his information from contemporary historical records, oral history, and the memories of older Eskimo men. The picture that emerged was of the war of “all against all,” as Hobbes put it: the bands under investigation fought one another; they fought Eskimo groups from further away in Alaska and Siberia; and they fought the Athabaskan Indians to the east in what is now the Yukon. Warriors typically wore body armour consisting of plates cut from bone or ivory and strung together like chain mail under their outer garments. There was at least one war a year somewhere in the region, and attacking parties might travel for many days and could be as big as fifty men, though fifteen or twenty was more usual. Alliances between bands were constantly forming and shifting as rival groups tried to gain numerical superiority, and there were occasional pitched battles in which lines of men would face each other. Much more common, however, were dawn raids on villages, which were frequently located in places with difficult access. It was not even uncommon to dig escape tunnels between the dwellings.
The ultimate goal of pre-twentieth century warfare among the native people of Alaska, according to the older Eskimo men interviewed by Burch, was nothing less than the annihilation of the opposing group: prisoners were taken only if they were to be kept for later torture and killing, and women and children were not normally spared. Burch was unable to estimate the proportion of the total population that ultimately died from this kind of warfare, but there is physical evidence (including mass graves) that massacres did occur.  And that, unfortunately, just about brings us to the end of the direct or oral evidence about warfare among hunter-gatherers, because the Arctic (where farming was impossible) and Australia (where agriculture never developed despite forty thousand years of human settlement) were the only large parts of the world where there were still significant populations of hunter-gatherers by the time Europe and North America developed anthropologists. (It is estimated that 99 percent of the indigenous population of North America were already farmers at the time of Columbus’s voyages.)
There is one final group, the !Kung Bushmen, much studied and certainly not warlike in the present, who are frequently held out as a model of the hunter-gatherer as peaceful Noble Savage but numerous historical accounts attest that in the seventeenth, eighteenth, and even nineteenth centuries Bushmen bands were very warlike, fighting one another and even successfully fending off for considerable periods of time Bantu and European farmers seeking to settle on their lands.
One way to expand the database, so to speak, is to consider also what are generally known as horticulturalists or tribal farmers. These are groups that continue to get a good deal of their food from hunting but who also practise a simple form of slash-and-burn agriculture. This lets them stay in one place for some years rather than the mere weeks that pure hunter-gatherers can manage. Their villages are more elaborate than hunter-gatherer camps, and their material possessions are more bulky and varied because they don’t have to be able to carry everything they own. In the most important ways, however, they remain on the far side of the gulf that divides prehistoric groups from agricultural mass societies. They are egalitarian cultures in which every man is both a hunter and a warrior, and their numbers are small. Individual villages are not much bigger than hunter-gatherer bands, because otherwise they would hunt out the nearby game too fast. And the ethno-linguistic groups (tribes) to which they belong rarely exceed a few tens of thousands. They marry out, and as with hunter-gatherers it is generally women who move to their husband’s group. Where hunter-gatherer groups will often come together for a few weeks each year in some place where resources are seasonally plentiful to party and match-make, horticulturalist villages tend to invite one another to feasts for the same purpose. They have no formal leaders (though obviously some individuals will be more persuasive or influential than others), and they make their decisions by discussion and consensus. In a sense, they are just less mobile hunter-gatherers.
There aren’t many horticulturalists left on the planet either: in most places, the transition to full-scale farming and much bigger societies was quite rapid and happened thousands of years ago. Those who survived into modern times were found mostly in isolated and resource-poor places like the Amazonian jungle and the New Guinea highlands – and wherever they were found, they were continually at war.
Suddenly I heard shouts: the enemy, the enemy. . . . The men had gone running to meet the enemy . . . [the men of the group are defeated and flee, and the women and children scatter to escape capture]. . . we could not flee any more; the Karawetari [the enemy] were by now quite close [the speaker’s group of women and children are surrounded and captured]. . . . Then the men began to kill the children; little ones, bigger ones, they killed many of them. They tried to run away, but they caught them, and threw them on the ground, and stuck them with arrows which went through their bodies and rooted them to the ground. Taking the smallest by the feet, they beat them against the trees and rocks. The children’s eyes trembled. . . . They killed so many.
A captive of the Yanomamo, 1930s 
The Karawetari and their victims were all members of the Yanomamo tribe, some twenty thousand horticulturalists who live in the Amazonian rain forest along the upper reaches of the Orinoco River in Venezuela and Brazil. Wars between their villages (average population around ninety people) were endemic until quite recently – the account of a raid above is from a white girl who was kidnapped at the age of twelve and lived among them in the 1930s – but as with all hunter-gatherer and horticulturalist warfare, the level of organization was low and discipline poor. Raiding parties often broke up before reaching their destinations, and clashes might result in only a minor injury or two. To the casual observer, the whole phenomenon of Yanomamo warfare could seem unserious – but when they got it right, with both surprise and numbers on their side, attackers could eliminate whole villages, killing or driving off their men, absorbing the women into the victorious village, and killing the younger children.
Was Yanomamo warfare serious? Why else were villages routinely fortified by building the houses in a closed circle opening onto a central courtyard? Why else were buffer zones averaging thirty miles maintained between villages for safety’s sake? Why else were the Yanomamo (just like chimps and hunter-gatherers) reluctant to venture too far into the buffer zone when not in large groups, even though it meant that much of their territory was unusable? And despite all these precautions, warfare took just the same cumulative toll that it did among the Murngin: anthropologist Napoleon Chagnon, who studied the Yanomamo in the 1960s, estimated that the death rate due to warfare was 24 percent of the men and 7 percent of the women. 
Chagnon’s findings have been bitterly disputed by rival anthropologists, who even accused him of instigating the warfare he observed among the Yanomamo, but the dissent seems driven largely by excessive loyalty to Rousseau’s hallowed vision of the Noble Savage. In any case, there is another, less controversial group of tribal farmers halfway around the world who displayed exactly the same behaviour.
The people of the New Guinea highlands are not strictly speaking horticulturalists, since the isolated mountain valleys where they live filled up with farmers long ago. Groups like the Mae Enga live at a population density of around a hundred people per square kilometre (compared to less than one person per square kilometre for Yanomamo tribal farmers, for hunter-gatherers, and for chimpanzees). As a result, there is little left to hunt: they grow yams and raise pigs for a living. But in most social and cultural respects they belong with the tribal farmers, not with the peasants of mass civilization. Their dispersed clan settlements, the equivalent of the Yanomamo villages, are only a couple of hundred people strong, and each is a separate political entity with sole responsibility for its own survival. The settlements are stable enough for complex alliance systems to form, however, and when prospectors first crossed the mountain barrier and discovered the New Guinea highlanders in the 1930s, warfare among them was constant. Indeed, people had become so tightly squeezed into their confined world that buffer zones between villages were down to something like half a mile, not the thirty miles of the Yanomamo.
Battles among the Mae Enga were often so tentative and indecisive that to the anthropologists who first studied them they seemed almost like play – the serious soldiers of civilized states don’t call off a battle just because it starts to rain heavily. Each party to a dispute showed up at a designated “battlefield” with all its allies, sometimes amounting to several hundred male warriors plus women to cheer them on, and they proceeded to form rough lines and run at one another. But it was by no means a battle to the death, and indeed the whole day’s “war” was usually called off if somebody was seriously injured or killed. So the initial conclusion of anthropologists who went to study them was that this was a ritual activity, not real war.
Later, anthropologists began working out genealogies and asking how each person died, and it turned out that 25 percent of the men and about 5 percent of the women in Mae Enga groups died from warfare. The highly choreographed “battles” look relatively harmless, but if you fight a dozen such battles a year, you still lose a lot of people in the long run. Moreover, it turned out that these staged confrontations were mainly a way to measure the strength of the opposing alliance. If the rival alliance looks about as numerous as your own, then everybody goes home again and forgets about it – but once in a while one side is severely diminished by defections, and it’s clear that the other has a decisive numerical advantage. At that point, it gets serious, and choreographed daytime battles give way to the nighttime or dawn raids aimed at exterminating the entire rival group. Nor was the warfare really indecisive. About 30 percent of independent social groups – villages, in other words – became extinct each century, either because they were massacred to the last man (and the women taken by the victors), or more commonly because attrition wore them down to the point where they lost a battle decisively and the survivors fled to take refuge with distant relatives, abandoning their territory.
It’s a pity that more hunter-gatherer and tribal farmer societies did not survive into the present or at least the recent past, so that we had a statistical sample of such societies and could be certain about our conclusions, but the available evidence argues strongly that our ancestors have been fighting wars since long before the rise of civilization. Indeed, the question arises: have we always done it? Does warfare among humans and proto-humans extend all the way back to the point five or six million years ago when our lineage diverged from that of modern chimpanzees?
We cannot answer that question about the deep past from the archaeological evidence we now have, and it is unlikely that we ever will. But by 750,000 years ago, some of the fossilized remains of Homo erectus found in Europe show signs of violence that might well have been inflicted by human weapons, particularly depression fractures in skulls that could be the result of blows from clubs. There are also numerous cut marks on human bones that suggest de-fleshing and cannibalism, which on evidence from later, fully human groups is likely to be associated with killing. Human awe in the presence of death, presumably a consequence of the fact that we, unlike our primate relatives, live with the certain knowledge that we ourselves must die, led us from very early times not only to bury our dead but to surround the killing of human beings with ritual. Complex purification rituals for warriors who kill are a common feature of pre-civilized groups like the Yanomamo, and cannibalism, as a way of assimilating and/or propitiating the victim’s spirit, seems to have been equally widespread. Evidence for cannibalism among our proto-human ancestors does not automatically mean they were acting from the same motives and in the same context of constant warfare, but it is suggestive.
By the time of the Neanderthals, the evidence gets stronger. Fossils found on several continents and dating back between forty thousand and one hundred thousand years seem to suggest death from injuries inflicted by human weapons – spear wounds, a stone blade lodged between the ribs – and there has even been a mass burial found in France. Indeed, more than 5 percent of Neanderthal burials show violence of one form or another, and since many violent deaths do not leave marks on the skeletons, that could be taken to mean that warfare bulked as large in the lives of Neanderthals as it did in the lives of relatively recent hunter-gatherers. We can have our suspicions, therefore, but we cannot really know for certain until we reach Homo sapiens – and then the evidence is overwhelming. 
How did we miss it for so long? How could Quincy Wright, who studied data from 633 primitive cultures for his monumental work A Study of War, conclude that “the collectors, lower hunters and lower agriculturalists are the least warlike. The higher hunters and higher agriculturalists are more warlike, while the highest agriculturalists and the [pastoral peoples] are the most warlike of all”? 
Rousseau has a role in it, certainly: we want to believe in the Noble Savage because it would mean that human nature is peaceful and war is just an invention of civilization. The contempt of people who know “real” war in the modern style for warriors who would rather run away than stand and die plays a part in it as well. But mainly we just didn’t do the arithmetic; we didn’t count up the cumulative death toll of the battles and raids.
So why did they do it? It would be arrogant and ignorant to assume that “primitive” people everywhere habitually threw their lives away in purely ritual activities – as if hunter-gatherers didn’t love their lives as much as we do, or were too stupid to understand the consequences of their actions. There must be logical reasons why they have waged this sort of warfare across the millennia on every continent. It would help if we knew what the reasons were, because it’s clear that modern human beings did not invent warfare. We inherited it.
[Yanomamo] villages are situated in the forest among neighbouring villages they do not, and cannot, fully trust. Most of the Yanomamo people regard their perpetual intervillage warfare as dangerous and ultimately reprehensible, and if there were a magic way to end it perfectly and certainly, undoubtedly they would choose that magic. But they know there is no such thing. They know that their neighbours are, or can soon turn into, the bad guys: treacherous and committed enemies. In the absence of full trust, Yanomamo villages deal with one another through trading, inter-marriage, the formal creation of imperfect political treaties – and by inspiring terror through an implacable readiness for revenge. 
Just change the names, and that would serve equally well as a description of the relationship of the great powers in the years leading up to the outbreak of World War I in 1914. Remove the details about trading and political alliances and the introspective bits about how the Yanomamo feel about their predicament, and it’s equally good as a description of the relations between the Kasekela and Kahama bands of chimpanzees in the early 1970s before the latter band was destroyed, and of relations between chimpanzee bands in general. In fact, it’s also a reasonably good depiction of the relationship between neighbouring packs of wolves, prides of lions, and packs of hyenas. This is a seriously disturbing thought, but we might as well face it: territory is important, and predators play for keeps.
The “predator” distinction is important: this phenomenon of raiding and waging “war” against other members of the same species occurs only among predators. Moralists will start looking for the mark of Cain, but pragmatists would simply observe that if you are not equipped in some way to kill members of other species, you probably cannot easily kill members of your own either. Thus, for example, only two species among the great apes, humans and chimpanzees, routinely hunt, and they are also the only two primate species that regularly engage in intra-species killing. Why these predators (and some others) make a kind of war is a difficult and contentious question, but the how is simple: they do it because both their physiology and their group-living habits make it easy for them to do so.
Lethal claws or teeth are not the sole issue. Tigers, hawks, weasels, and other predators that live alone or in single-family groups rarely experience fights to the death among adults. It is simply too risky: equally well-armed individuals are equally likely to die as a result of the fight, and no advantage that could come from winning the fight is worth a 50 percent risk of death. Dominance struggles among predators that live in groups do not usually lead to deaths, either; this would obviously not be to the advantage of the group, so evolution has generally equipped such species with very recognizable submissive behaviours that enable the loser in a dominance contest to switch off the winner’s aggression and escape with his life. But these gestures of submission do not have the same power to defuse aggression in confrontations between members of different groups, packs, bands, prides, etc., nor are such confrontations about any individual’s place in the dominance hierarchy (which is internal to each group). So when do killings happen between groups, and why?
The only large animals that regularly and deliberately kill adult members of their own species are predators who live in loosely related groups of variable size. When the whole group is together, no rival group would dream of running the risks involved in attacking it. Often, however, they have to spread out in search of food, and individuals get separated from their home group for a time. They then run the risk of encountering a party of several adults from a neighbouring group.
The lions [of northern Botswana’s Chobe National Park] live in prides that defend their territory against neighbours. The prides are parties of female kin. . . . During a zebra hunt one night, two lion prides converge near the boundary and a fight ensues. In the chaos, an old female of the Maome pride becomes isolated by intruders behind the battle lines. We see her surrounded and held captive at first by three hostile lionesses, eventually by as many as seven. And her death is particularly distressing because it looks so deliberate. She starts alert, erect, snarling, though already bleeding from the shoulder. Naturally she can face only one way at a time. She turns repeatedly to check behind her. She is wise to check, for lions can die from a single bite to the spine, but whenever her head is turned, someone swipes at her. The attempt to stop one antagonist merely opens the door for another. Like some hideous children’s game, everyone takes a turn striking or biting, while the surrounded victim hopelessly spins and writhes and rears and twists. She is prevented from escaping, constantly herded back to the center. Motsumi, the leader of the Maomi pride, approaches once in an apparent effort to rescue her pride-mate, but she is quickly chased off. And the victim is tormented in this fashion for several hours before she weakens and finally collapses, exhausted, finished. The female killers leave, and then the corpse is eaten by hyenas. With minimal risk to themselves, the pride has relentlessly caused a rival’s death.
The killing of a lioness in the 1992 nature film Eternal Enemies 
Lions do not normally eat lion: the confrontation was not about food, and the corpse of the old female was left for hyenas to eat. Similar killings occur among hyenas (whose packs, like lion prides, are groups of related females) and among wolves (whose packs are built around male kinship groups). They also occur between bands of chimpanzees and of human hunter-gatherers (both founded on groups of male relatives). In all of these cases, the main enabling factor is that an isolated individual from one group can on occasion be caught and killed without much risk by a gang of individuals from the rival group. However, only the two great ape species carry out deliberate raids and only the humans sometimes go beyond many-on-one ambushes and engage in many-against-many fights. What drives all this behaviour? A lot of the answer comes from Darwin and his modern successors.
A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes, and this would be natural selection.
Charles Darwin,The Descent of Man (1871) 
Modern evolutionary theorists, building on the foundations laid by Darwin, emphasize that while evolution shapes an entire species, the multitudes of decisions that go into defining the future of a species are all made by individuals. This has an important consequence: these billions of individual decisions are each made with the goal of perpetuating not the species but the genes of the particular individual making the decision. This approach to evolutionary theory, vividly summarized for the general public in Richard Dawkins’s The Selfish Gene, immediately explains why infanticide, so apparently counter to survival for a species and yet so widespread, can make evolutionary sense. For the individual male lion or gorilla who takes over a dead rival’s harem, killing all the former proprietor’s offspring is perfectly sensible, since the females he has inherited will then stop wasting energy on raising the dead male’s offspring and become fertile again, allowing him to get started on ensuring his own genetic future.
Does the same genetic logic explain why it makes sense for predators belonging to one band, pack, or pride to kill a member of a neighbouring band when they can do so safely and economically? What is in it, with regard to perpetuating their genes, for the individuals in the group that does the killing? They do not directly gain access to better reproductive opportunities, obviously, but the killer’s group does gain a potential advantage over the neighbour group by making it one adult member weaker in a world of almost constant scarcity and competition for resources. And since the adults who do the killing are probably related to one another, if their group does well, so do their genes.
It’s important to note that this sort of group is just a temporary coalition of individuals, one sex of whom are related (males among primates and wolves, females among lions and hyenas). The group may persist for several generations, grow to the point where it splits into two separate groups (which may rapidly become rivals), break up, or die out, but it has no permanent genetic existence in the sense that a species does. Nevertheless, it is a stable enough social grouping that its collective fortunes will play a large role in deciding the fate of the individual member’s genes, so it pays to weaken rival groups by killing their members when the opportunity arises and the risk is low.
Among group-living predators, therefore, there has been selection for individuals who engage in this sort of behaviour, which is much more common than anybody realized even a few decades ago. It is most extreme among the primate predators, chimpanzees and humans, who carry out deliberate raids against rival groups, perhaps because they are also the most intelligent of the predators. But what underlies all these arguments about competition and evolutionary advantage is the assumption that resources will be scarce at least part of the time, and that some groups will lose out when times are bad.
The world was never empty, and food was always limited. The fact that human hunter-gatherers, like other predators, lived at very low population densities compared to the tightly packed farmers of a later time does not mean that there was ample space for all the bands to spread out and avoid competition over resources. Once in a while there would have been a few generations who had that happy experience, just after human beings had moved into previously inaccessible territory for the first time, but it never lasted long. The territory would soon fill up with people living at the maximum density that could be sustained by the available game resources, and then the old reality returned.
This is not to say that our early ancestors waged a kind of war against one another because they knew that population pressure would ultimately bring them into conflict with neighbouring groups (so we might as well start killing them now whenever we get the chance). In fact, even the hunter-gatherer groups that we know something about rarely explained their wars in terms of resources, generally blaming them instead on insults, quarrels over women, and the like. Most of the time, people probably just went on doing what their ancestors had done since long before we were human, driven by an evolutionary logic that had shaped their social structures as well as their emotional reflexes. But as the millennia passed and people’s ability to articulate how their world worked grew, at least some of the wars among human groups would gradually have become more considered and more consciously related to current or anticipated conflicts over food supplies.
To account for how these conflicts become chronic wherever humans lived, we do not even need to prove that they have links with the pre-human past or with the behaviour of other predator populations. We merely need to establish three propositions. The first is that human beings have the physical and psychological ability to kill members of their own species. The second is that human populations will always grow up to the carrying capacity of the environment and beyond. The third is that human beings are no better at conserving their environment and preserving their long-term food supply than any other animal. If these three things are true, then prehistory will have been filled with conflicts between human groups over resources, and many of those conflicts will have been violent.
Well, we know that human beings can kill each other. The second proposition, that human populations prior to modern times always tended to grow unless checked by some outside force like famine or violence, cannot be absolutely proved one way or the other, but it has the ring of truth. We certainly do not know of any pre-modern human group that succeeded in halting population growth over the long term by voluntary measures, nor do we know have many examples of such restraint among other animal species, many of which go through regular cycles of population boom followed by population crash.
The population would have grown much more slowly among prehistoric hunter-gatherers than it did at the peak of the twentieth-century population boom, when the human race tripled from two billion to six billion in only fifty years. Hunter-gatherer mothers, who found it hard to deal with more than one toddler who had to be carried, spaced the birth of their children as much as four years apart by nursing for a very long time: the average woman might have as few as four or five children in a lifetime. Almost all human societies practised infanticide until recently – cross-cultural surveys suggest that an average of about 15 percent of babies (always many more girls than boys) have died in this way in societies ranging from hunter-gatherers to nineteenth-century England  – but infanticide among humans is a decision that relates to family rather than group welfare, not a deliberate means of population control. Even allowing for infanticide, child mortality rates were well below 50 percent among hunter-gatherers who were not exposed to the epidemic diseases of mass civilization. So populations usually grew slowly but steadily – and given the magic of compound interest, it would not have taken many generations for hunter-gatherers to reach the carrying capacity of any given territory. 
The mere fact that humans and proto-humans did not remain in their original home territories in Africa, but instead spread into every environment on the planet that could support the hunter-gatherer way of life, however inhospitable, is proof in itself that populations grew. Why else would some bands have moved on? Where else would the extra people to fill up the new territories have come from? But if populations grew and resources did not (since hunter-gatherers had no technologies to increase the productivity of their territories), then problems lay ahead. Their numbers would eventually be contained either by starvation or by violence.
There is a powerful mythology that insists that “native peoples,” whether hunter-gatherers, horticulturalists, or early farmers, were in tune with nature and the guardians of their environment. Unfortunately, there is no empirical evidence that early humans were any more conscious of the moral imperative to preserve the environment than the other animals that they shared the environment with. Hunter-gatherers were limited in the ways in which they could damage their environments, but within those constraints they were even more ruthless than modern human beings. The most striking examples are the “New World blitzkriegs” – the mass extinctions of large game animals – that followed the arrival of the first modern humans in all the continents and islands outside the old hunting grounds of proto-human groups in Africa and Eurasia. In the world-island where successive versions of our ancestors and very close relatives evolved and spread over millions of years, from Homo australopithecus and Homo erectus to Neanderthal and Cro-Magnon, most prey animals had time to adapt to the gradually improving skills of human-like hunters (though there may have been occasional extinctions in which human hunters were a significant factor). But when modern human beings arrived in parts of the world that had never been accessible to earlier human groups, mostly by boat, the carnage was astonishing. The local animals had no knowledge or fear of human hunters, and the hunters showed no restraint whatever.
When the first human beings arrived in Australia over fifty thousand years ago, in the Americas about fourteen thousand years ago, in the large Caribbean islands four or five thousand years ago, on the great island of Madagascar about two thousand years ago, in the Hawaiian islands around AD 300, and in New Zealand about AD 700, the result was invariably the same: the extinction of many or most of the larger animal species. It took as little as five centuries in smaller environments like New Zealand, where all the giant moas vanished, and Madagascar, where some two dozen species including giant lemurs, giant tortoises, and a local variety of hippo became extinct. In the Americas, two entire continents, it took over a millennium before the giant ground sloths, mastodons, camels, woolly bison, and even the horses were all hunted out, but that is still just the blink of an eye in the normal lifespan of a species. Surrounded by plenty on the hoof, the hunter-gatherers’ numbers grew almost exponentially – the frontier of human occupation was probably moving forward by several miles a year – and the numbers of the more vulnerable animals dwindled toward extinction. Some people try to dismiss the evidence of the blitzkriegs with talk of climate change and disease, but such arguments do not really hold water: the coincidences of human arrival and mass extinctions in so many places admit of no other explanation.  Besides, recent ethnological investigations of surviving hunter-gatherer groups like the Hadza of Tanzania show that the same behaviours persist today.
[T]he Hadza give little attention to conservation of their food resources. When women dig up roots, they do not attempt to replace any portion of the plant to grow again. When they gather berries, heavily laden branches are often torn from the trees and carried back to camp. . . . When a nest of wild bees is found and raided for its honey, no portion of the comb is left to encourage the bees to stay on. . . . In hunting, no attempt is made at systematic cropping. . . . There are no inhibitions about shooting females (even pregnant females) or immature animals. . . . If two animals are killed on the same day, the more distant one may be abandoned.
An anthropological investigation of Hadza attitudes to the environment, 1960 
Why would anybody expect anything different? Human beings are animals before they are anything else, and animals are not ecologically conscious. Animals do not live “in harmony with nature”; they live in a Darwinian dialectic with the other species around them, permanently threatened by predation and/or hunger, and many species ride the roller coaster of large population booms followed by big die-offs. They often alter their environments, too, sometimes so drastically that they suffer for it, but often with beneficial results for themselves. Prehistoric human hunters, for example, used their mastery of fire to burn down immense tracts of woodland in order to create the more open terrain preferred by the big grazing animals that were their favourite prey. But it is fantasy to imagine that they actively “managed” their total environment, or understood the full implications of their impacts on it, or indeed gave the matter much thought at all. They probably did worship nature, but that does not mean that they understood it.
Even in newly inhabited areas, therefore, human populations would grow and the available resources, both game and other food, would come under increasing pressure. They would already be engaging in low-level warfare of the traditional sort with their neighbours, making sporadic raids and restricting their hunting to the central parts of their territory for safety. The steady toll from warfare plus a fair amount of infanticide might keep their populations sufficiently in check to avoid serious hunger so long as times remained good. But even a brief interruption in normal food supply due to changing weather patterns, alterations in animal migration routes, or other unpredictable factors would create an instant crisis, since most of the foods people eat cannot be stored. In a matter of weeks or months everybody is hungry all the time, and since human beings are gifted with foresight, they know what lies ahead for most of the group if this goes on. They also know that other groups in the vicinity are facing the same problems. It is probably at this point that warfare became for the first time a fully rational (and utterly ruthless) activity. Almost everybody will fight rather than watch their children starve.
How will fighting help? Those universal no-man’s lands between the groups will account for over half the available territory, and that is exactly where the surviving game will congregate in a heavily hunted region. The only safe way to exploit that game is to eliminate or drive away the band on the far side of the buffer zone, and that is the course that must have been chosen by tens of thousands of desperate bands over the past million years. If they were competent and lucky, it ended with one surprise attack, a massacre, and total victory. If not, it became a long attritional struggle, perhaps with both sides drawing allies into the conflict – and the fact that this may not happen often is less important than the fact that it happens repeatedly, and that one day your neighbours might do the same thing to you. Soon the suspicion, the alliance-making, and the warlike demonstrations are a routine part of life, and serious warfare is a permanent possibility. ___________________________________________________________________________
Primatologists have no reluctance about explaining the warlike behaviour of chimpanzees in terms of evolutionary advantage – that is, that members of a troop that is good at aggression will probably have better resources for raising their young and passing on their genes – even though nobody imagines that chimpanzees are making conscious calculations of this subtlety in their heads. Neither are they puzzled when they encounter chimpanzee bands that are attacking their neighbours at a time when resources are not particularly scarce: whether this behaviour is just a deeply entrenched cultural pattern or partly a genetically driven one, it’s certainly not something that chimps would be able to turn on and off like a tap.
Traditional anthropologists, by contrast, were hugely reluctant to accept that prehistoric human groups might have had a deeply entrenched cultural tradition of waging war with neighbouring bands that rewarded groups who were good at it with a better prospect of surviving hard times and perpetuating their genes. Captivated by the notion of the Noble Savage, they insisted that the people they were able to study directly, while they did wage something that looked like war against one another, were actually engaging in a ritual activity – part art form, part healthy outdoor exercise for underemployed hunters — that had nothing to do with achieving economic or political aims. “The idea of conquest never arose in aboriginal North America, and this made it possible for almost all these Indian tribes to do a very extreme thing: to separate war from the state,” wrote anthropologist Ruth Benedict. “. . . Any man who could attract a following led a war party when and where he could, and in some tribes he was in complete control for the duration of the expedition. But this lasted only until the return of the war party. The state . . . had no conceivable interest in these ventures, which were only highly desirable demonstrations of rugged individualism.” 
The “state” did not really exist in most American Indian tribes, but the point of emphasizing the total separation of warfare and the state was to prove that whatever the Indians were doing, it was not the terrible phenomenon that we know as war. Two other early anthropologists, Ernest Wallace and E. Adamson Hoebel, were making essentially the same point by explaining that the highest honour a warrior could gain among the Indians of the Great Plains was not to kill the enemy but to “count coup” – to approach the enemy without weapons and touch him with a stick or his hand. The purpose of inter-tribal warfare, in other words, was to give warriors an opportunity to demonstrate their courage. Thus the most famous and respected Comanche warrior of his time was a man who acquired a blanket made by the Utes, his tribal enemies, and used it to walk in among them unarmed.
After dark, he drew his blanket over his head and sauntered into the Ute encampment. From within one of the lodges he heard the sound of a hand game in progress. Protected by his disguise, he walked right through the door to join the spectators. Nobody paid any attention to him. Casually and slowly moving about he touched one after another all the Utes in the lodge. When he had touched them all, he strolled out and rejoined his friend. He had counted coup on twenty enemies at once. It was a great deed. 
Well, of course. Cultures where warrior values dominate are bound to include various customs and institutions that appeal to the warrior mentality, from counting coup to jousting to duelling, even though these activities are not strictly functional with respect to winning a war. That does not mean that the wars these cultures wage are meaningless rituals. The battles they fight may be badly organized and indecisive by the standards of more disciplined cultures, and the warriors may be more inclined (or just freer) to run away when things look bad in order to fight another day. But people die in significant numbers, and in the end real things get decided: some bands or tribes expand and prosper, while others shrink or disappear.
The fact that the bands and tribes caught up in conflict generally explain their wars by recounting insults exchanged, women stolen, or ancestral enmity does not mean that the wars lack deeper and more serious causes. At one level, World War I was just caused by Gavrilo Princip assassinating Archduke Franz Ferdinand, but we all know that there was also another level of causation. There almost always is.
The kind of war that was waged by our early ancestors and by our more distant evolutionary cousins seems almost childlike to the modern mind. Either they didn’t understand what their wars were really about (foolish of them), or they actually were just fighting over stolen women and or some insult to the group’s honour, as they generally said they were (even sillier). Nor did they ever fight “properly,” veering between formal battles in which everybody was careful not to get too close to the enemy, raids in which a group of hunters ambush and murder a single opponent, and occasional sneak attacks, often on sleeping people, that ended in massacre. There was little strategy, less discipline, and not even much of the kind of courage that we expect in the soldiers of civilization. To generations of military historians raised on the doctrines of Clausewitz, this cannot be “true” war.
On the other hand, there are those appalling statistics: 24 percent of Yanomamo males and 7 percent of females killed in war – taking the two sexes together, a fatal casualty rate of 15 percent per generation. Among the Murngin of Australia, 25 percent of men killed in battle. Twenty-five percent of men and five percent of women killed in warfare among New Guinea highlanders, and one-third of all existing independent groups destroyed by war each century. (Not to mention an estimated 30 percent fatal casualty rate from warfare among male chimpanzees.) If this is not “true” war, it is nevertheless a very bad kind of war.
Besides, the differences between us and our ancestors are smaller than they seem. The primitives may have been unclear on the underlying causes of the wars they fought, but the spectacular diversity of opinion among Americans about their own government’s motives in invading Iraq in 2003 suggests that this is not solely a problem of the ancients. Standing your ground under fire until you are killed is certainly a modern behaviour, but not necessarily a clever one. And on the fundamental issue of casualties, prehistoric warriors leave the soldiers of civilization standing: few modern societies have ever sustained a 15 percent death rate from war in a single generation, let alone in every generation.
For a country the size of the United States today, 15 percent fatal casualties per generation would work out at about a million deaths from war per year, every year, forever. In fact, the United States has not lost a million people killed in war in its entire independent existence, now more than two and a quarter centuries. Even countries that have borne the brunt of heavy bombing and major land warfare on their own territory in recent wars rarely approach this level of losses – although most of the countries of central and eastern Europe from Germany to Russia came close during World War II – and no modern society has experienced this level of violent deaths over an extended period of time. The lives of our prehistoric ancestors were utterly immersed in war – intermittent, low-level war for the most part, but the deaths were real enough – and fear would have been their constant companion.
We have long been taught to believe that the rise of civilization led to an intensification of warfare (nasty moderns vs. noble savages), but the evidence actually suggests the opposite: that the creation of mass societies sharply reduced the casualty rate from war. Civilized societies fight with armies, which include a far smaller proportion of the adult male population than the all-in scrum of the warrior band, and for most of history those armies fought only one or two major battles a year. Casualties were high on the actual day of battle, but much lower than those suffered by hunter-gatherers in the long run. In fact, there have not been many generations of human beings since the rise of civilization in which the direct loss of life from war has exceeded 2 or 3 percent of the population. (The principal pre-twentieth century exceptions were during the recurrent nomad invasions.)
There is also a less obvious, almost mechanistic explanation for the steep fall in the death toll from war. Tiny hunter-gatherer societies of thirty or forty people – a couple of hundred at most, in the case of horticulturalists – had absolutely no strategic depth: everybody lived on the front line, so to speak. In a settled agricultural society of a million people, by contrast, as few as 5 percent of the population would live within a day’s walk of borders with potentially hostile neighbours. Such societies simply could not get at each other as a totality; at least at the beginning of a war, they could fight only at the edges of their territories, with armies. The only recent conflicts in which a huge casualty toll occurred without much resort to heavy weapons have been in countries where rival populations were intertwined in ways that left everybody close to a potential enemy: for example, Yugoslavia’s civil war during World War II (which killed an estimated two million people although there was not a single major battle fought on Yugoslav soil), or the Rwanda genocide of 1994 (in which 10 percent of the population was murdered by their neighbours in only a few months). Most of the time, bigger countries with more homogeneous cultures were a lot safer.
Until recently. Over the past century, we have seen industrial countries develop the ability to mobilize their vast resources and deliver armies of millions to the battle fronts and then develop the technologies to deliver the battle to the enemy’s “home front” from the skies. Suddenly, advanced societies are back in the position of their earliest ancestors, with every part of their population equally exposed to the possibility of an instant and horrible death in war. After ten thousand years we have come full circle, and everybody is once again in somebody else’s sights all the time. Even the very largest countries must live with the constant possibility of extermination. It’s a tiny risk in any one year, just as it was for hunter-gatherer bands, but cumulatively it is serious and deeply worrisome.
So are we doomed, then? Not necessarily. We have learned and changed during the thousands of years we have spent in the mass societies, and we are not trapped in the Malthusian dilemma of the hunter-gatherers: we do not actually have to fight to survive. War clearly has deep roots in our human lineage, but that no more condemns us to perpetual war than a long tradition of infanticide condemns us to a future of baby-killing. So much of our mentality and so many of our institutions are built on the assumption that war is a constant that it’s very hard to break out of the old pattern, but self-interest and perhaps even empathy push us away from war and toward more cooperative behaviour. The little tribes of highland New Guinea went on fighting their vicious little wars in the early 1940s even as the larger war raged around them, recounts Peter Richter, an expert in cultural evolution at the University of California at Davis, “but when, after World War II, the Australian police patrols went around and told people they couldn’t fight any more, the New Guineans thought that was wonderful. They were glad to have an excuse.”