Do we, like the ants, have organized aggression embedded in our genes? Is it a part of human nature? Or is war learned behavior? Can we ever tell when war began, and where?

By dawn the warriors had assembled outside their quarters. Either by signal or by common understanding, they began the march to the colony they were going to raid. Upon reaching the territory of their victims, they were met by defenders, who put up a tremendous fight, cutting relentlessly at the legs of the attackers. The raiding warriors, however, were bigger and better fighters and soon were piercing the armor of the defenders at will. Yet their primary aim was not to kill, but to steal the defenders’ infants and carry them back to their own colony. There the youngsters would grow up to be slaves, spending their lives finding food for the warriors and even feeding them. Meanwhile the warriors—like proud imperial paladins—would dedicate themselves to an endless search for more slaves.

Here we find the origins of true war. Virtually all the prerequisites are present: a complex social structure, coordinated aggression, political and territorial overtones, and a lust for property. Yet the practitioners are only a few centimeters long. They are Polyergus ruféscans—Amazon ants. For between 50 million and 100 million years, members of this species and their cousins Myrmica, Formica, and the rapacious Eciton and Dorylus have lived by fighting. The manner in which they fight defines what we now call warfare.

These ants have no choice—their genes predestine them for a martial existence. Is this also the case with humans? If it is true that the martial impulse resides in our genes—that we are in effect born warriors drawn irresistibly to war—there is little hope for the future of our species in a time of nuclear weapons. On the other hand, if it can be shown that we learned to wage war, there is reason to hope that we can learn not to. For now there can be no definitive answer, nor can we expect one until the science of genetic mapping becomes far more advanced. Nonetheless, we can glimpse outlines of a solution by studying the past. There is considerable disagreement as to how human warfare began, but if we look carefully and selectively at the main arguments, and are precise about what we define as “war,” then the origins of war can be approached, if not exactly pinned down.

“Nothing in the habits of man seems more ancient than war,” the military historian Bernard Brodie has written, and until very recently the history of thought had produced little to contradict this notion. The ancient Creeks, the world’s first self-consciously analytic people, simply took wars for granted, assuming that men had always fought them. Even Plato and Aristotle, who did consider the origins of city-state rivalries, declined to treat warfare as a subject in and of itself. Wars were important; war was not. Similarly, Leonardo da Vinci denounced warfare as bestialissima pazzia (the most bestial madness) but did not question its age or inevitability. Indeed, until the 19th century, Western cultures fatalistically included war, along with famine, death, and pestilence, as one of the Four Horsemen of the Apocalypse, scourges that had always been and always would be.

Only the coming of the concept of evolution caused people to question this basic assumption in any systematic fashion. Appropriately, it was Charles Darwin who suggested, in his 1871 book The Descent of Man, that rather than being innately blueprinted, war was subject to manipulation and improvement. In fact, Darwin considered war the prime driver of cultural evolution. In his view each martial innovation “must likewise to some degree strengthen the intellect. If the invention were an important one, the tribe would increase in numbers, spread, and supplant other tribes.” By 1896 Darwin’s follower Herbert Spencer went even further, arguing that the basic leadership/subordination behavior patterns necessary for centralized political systems first developed in primitive military organizations. However, by 1911 this assumption and the implied primacy of warfare as a force in the development of complex societies were cast aside by William Graham Sumner, who said war and peaceful pursuits developed side by side.

The most important thing about this intellectual give-and-take is not who was right or wrong but that war was no longer being treated like glaciation or the formation of mountain ranges. Rather, it had become for these evolutionary thinkers essentially a cultural institution whose roots could be discerned and whose development was primarily a function of learning. This was an important change, and it is probably not accidental that it coincided with the rise of the idealistic pre-1914 peace movement, which assumed that war could be progressively mitigated and eventually outlawed.

Meanwhile, the serious study of man’s cultural beginnings had just gotten under way. Darwin had performed field studies in the course of his animal research, but when it came to human societies the evolutionists were mostly armchair theorists, relying on written sources and their own intellects. Field anthropologists would later test these theories against hard evidence.

Basically, research relevant to the origins of war proceeded in three directions: ethnography (the observation and reporting of a people’s way of life), physical anthropology (essentially archaeology applied to the remains of humans and their precursors), and historically oriented studies (including philology, comparative government, and a more traditional form of archaeology that focused on what humans built or manufactured). In the case of ethnography, European travelers had for centuries been gathering information on societies that were discovered as Western culture expanded, but they had done so randomly and based on anecdote. Now, at the beginning of the 20th century, a group of pioneering anthropologists, among them W.H.R. Rivers and Franz Boas, produced careful and systematic studies of non-Western cultures, basing their findings on intimate familiarity with their subjects and on long and direct observation. Since the ultimate intent was to understand the evolutionary roots of our own cultural institutions by analogy with simpler societies, the bulk of subjects prior to World War II belonged to tribal groups, particularly tribal hunter-gatherers.

Ethnographers made several discoveries of real significance to our understanding of man’s attachment to warfare. First, they found that hunting-and-gathering cultures generally led a relatively low-key existence in which teamwork within the groups was paramount and hostility and aggression were muted. It has been argued that the apparent gentleness of contemporary hunting-and-gathering groups resulted largely from natural selection, whereby less aggressive groups became concentrated in remote locations, where they continued to pursue very basic life-styles. Nevertheless, the behavior of these people toward one another did much to undermine stereotypes of both the savage “savage” and his brutal ancestors.

Affability aside, these people, or at least the males among them, were still hunters by occupation and were found to be suitably equipped. Virtually without exception they possessed weapons. Indeed, in the entire course of ethnographic research, investigators have found only two small groups that lacked even weapons to hunt with—the Fhi Tong Luang of Southeast Asia and the Tasaday, a group of about 25 individuals living what appeared to be a peaceful arboreal existence in the Philippines. (The Tasaday life-style is now thought by some to have been a hoax perpetrated by the Marcos regime to boost tourism.)

As for the other groups studied, ethnographers found weapons to be not only the tools of the hunter but the means to manslaughter: Intergroup violence was observed to be part of the hunting-and-gathering existence. It was certainly not universal—and this is important—but lethal fighting between tribal groups did go on. Such combat took the form of extended blood quarrels, sporadic and highly personalized affairs, homicidal in intent and, occasionally, in effect, but lacking a sustained economic and political motivation. The goals of combatants were typically revenge and the capture of women. Ambush and raiding were the preferred modes of operation, and the target was frequently a single “enemy.” Pitched battles, when they occurred, represented tactical failure. The object was rout, not prolonged combat. Thus the attacking party would come close only if surprise was reasonably certain; otherwise the aim was to stay at long range and exchange missiles.

From the perspective of the participants, this made perfect sense. Combat was really only an extension of personal disputes. Armies were little more than collections of individuals, in most cases fighting more out of loyalty to some injured party than to the group and its aspirations. Because the participants lacked a stronger, more unifying purpose, the fighting potential of such a force was limited by the participants’ willingness to assume risk. Since the degreee of such willingness was usually low, this type of combat was inherently indecisive and produced few casualties.

All of this was duly noted by the ethnographers, who were nothing if not accurate observers. Yet they were also human beings, at times living in the midst of, or at least confronted with, the results of this mayhem. Even if casualties were few, they did occur. People they may have known were being killed, often horribly. The attacks and counterattacks persisted in a hopeless chain of violence, which must have suggested to these Westerners the futility, if not the true character, of their own culture’s martial conflagrations. Consequently, it is not hard to understand why ethnographers persisted in labeling these quarrels among their subjects as “wars.” Yet in doing so, they set the stage for later confusion. Ethnographers and those in related fields, such as sociobiology and physical anthropology, adopted an exceedingly inclusive definition of war, while historians and political scienctists were generally more selective. The two sides were not talking about the same thing, but at times this was not very obvious.

Meanwhile, ever since Darwin had set forth his theory explaining how life developed, a major element of evolutionary studies had been devoted to defining better the process by which man emerged from his primate ancestors. The first discoveries in the late 19th century of the fossilized remains of Neanderthal and then so-called Java man—both apparently transitional beings with apelike features—raised the hope of actually establishing physical proof of man’s evolution and transformed anthropologists into burrowing creatures digging for bones at the slightest provocation.

This prolonged search bore fruit first in 1924 and again in 1959 with discoveries of Australopithecus africanus, an apelike creature later established as a key figure on the evolutionary trajectory that led from apes to humans. Australopithecus was not very impressive to look at. Slight of build and probably no more than five feet tall, these hominids (as such ape-people are commonly called by anthropologists) was virtually without natural armaments, lacking even a decent set of canine teeth such as those of baboons. Yet they did possess one remarkable feature: All the physical data indicated that these nearly 4-million-year-old protohumans walked upright, probably as easily as we do. There is general agreement that their unique posture—which, among other things, freed their hands—was the critical break that separated them from the apes and set them on their own evolutionary way.

Yet the evidence also indicated that they were not walking on familiar ground. Found in association with the little hominids were the remains of antelope and other mammals specialized for life on grasslands. This indicates strongly that Australopithecus lived not in the tropical rain forests that are the customary homes of the great apes but on the savannas, with the teeming herds of herbivores and the big cats and other carnivores that preyed upon them. Why they left their ancient forest home is not clear, but it appears that they began their stay in this new and inhospitable environment as vegetarians. Perhaps they eked out a living gathering seeds, an occupation that would have made use of and improved their digital coordination. Still, food was probably scarce, and the danger from big predators virtually constant.

Hunger and fear drove them to change. It may have begun modestly with digging for grubs and progressed gradually to scavenging. But these human ancestors developed a taste for meat, and, of equal importance, at some point they learned to use weapons. It could well have happened in the scavenging stage, possibly in defense of carcasses brought down by a larger predator. Gradually the little hominids realized that previously useless objects such as sticks or bones, taken up in a hand preshaped for grasping, could be thrown or wielded with deadly effect. From then on, they took the offensive. The hominids became hunters.

It was an amazing transition. Although the weapon may not have been the first tool, it did mark the hominid line’s first great success with tools. Combined with Australopithecus‘s unique posture and superior intelligence, weapons transformed the little ape-people into truly dangerous beings. Once they began hunting, our ancestors moved quite quickly to big game, prey much larger than themselves. In conjunction with the remains of Australopithecus, anthropologists have found numerous skulls fractured by blunt instruments, indicating that the hominids attacked and killed the now extinct giant baboon. They also numbered among their victims antelope, giant sivatheres (horned giraffes), elephant-like deinotheriums, and other large mammals. They became, in short, accomplished and voracious killers.

So voracious, in fact, that a number of researchers concluded that Australopithecus and their hominid descendants employed violence with nearly equal ardor against each other. M.K. Roper, for example, analyzed the remains of 169 pre-Homo sapiens and concluded that one out of three in the sample had suffered injuries from armed aggression. Raymond Dart, the earliest discoverer of Australopithecus remains, went even further, calling our predecessors “confirmed killers.” Dart maintained that “the loathsome cruelty of mankind to man forms one of his inescapable, characteristic and differentiative features; it is explicable only in terms of his carnivorous and cannibalistic origin….

Significantly, this vision of human nature was passed to a brilliantly persuasive writer, Robert Ardrey, who, while on assignment in Africa, met Dart and was mesmerized by his version of the emergence of humans. The result was a series of compelling books published in the 1960s and 1970s— African Genesis, The Territorial Imperative, and The Social Contract—which popularized the accomplishments of physical anthropology. They also, incidentally, established in the public mind Ardrey’s theme that war was based on “a human instinct [territoriality] probably more compulsive than sex” and fueled by a genetic urge to “design and compete with our weapons as birds build distinctive nests.”

Ardrey made some good points, but most experts agree that his case was entirely overstated. For one thing, the whole concept of innate territoriality among humans or prehumans falls apart when subjected to close scrutiny, and while there may be some reasons to suspect that weapons development could have a genetic component, that is little more than a possibility. There is an even more fundamental objection to this blood-soaked picture of our prehuman ancestors: The studies on which it is founded use very small samples of very old and incomplete evidence. One can easily read a good deal more into these data than can be logically supported by practical models of the huntingand-gathering way of life. Certainly it is possible, even likely, that there was some lethal violence among hominids. The animal behaviorist Konrad Lorenz has theorized that since our progenitors were once not dependent upon killing for a living, the need for special inhibitory mechanisms against intramural bloodshed, present in a number of predators, was not anticipated in the ancestral gene pool. It follows that the introduction of armaments, with their death-dealing capacity, must have posed a great challenge to the primitive hominid social structure. Yet the survival of the strain from which humans evolved is prima facie evidence that they learned to keep the violence within acceptable limits.

Economic reality, if nothing else, must have set some limit on the duration and intensity of the bloodshed. The hunting-and-gathering way of life simply does not afford the long-term food surpluses necessary for extended military campaigns. Nomadic shifts in hunting grounds also precluded all but the simplest, most easily portable material goods, removing one major motive for armed aggression. Furthermore, the population density of prehumans was very low, hence contact between bands was probably limited and could be quickly broken off in case of hostilities. Unlike today’s hunter-gatherers locked in perpetual feuds with neighbors, early humans always had someplace else to go.

Even when fight rather than flight was the choice, it is logical to assume (for the economic reasons cited above) that the violence was analogous to the sporadic forays observed by contemporary ethnographers. Probably as weapons were improved—slowly during the Lower and Middle Pleistocene (from I million to 35,000 years ago) and then more rapidly in the Upper Paleolithic (35,000 to 10,000 years ago)—the deadliness of interpersonal combat did increase. But there is no reason to assume that it changed qualitatively or in terms of motivation, for it was hunting, not fighting, that drove improvements in weaponry.

Most important was the introduction of the bow. Deadly against game as large as antelope, the bow was also well suited to the hunter-gatherer’s brand of fighting. At once safe and lethal, it was the ideal weapon of harassment. A combatant might spend an afternoon shooting away at long range with little fear of injury. Yet if the opportunity presented itself, he could move in for a swift, silent kill. Therefore it comes as no surprise that the earliest surviving image of combat, a Mesolithic cave painting at Morella la Vella in Spain, depicts men fighting with bows. The picture seems familiar, for it is difficult to see the action as anything but confused and fleeting. The participants appear to be on the run, perhaps hoping to rip off a few quick shots before retreating. Indeed, the scene captures in a single visual metaphor the essence of primitive combat. But is this warfare?

Some would have it so. The military historian Arther Ferrill, for example, sees evidence of disciplined fighting forces attempting a double envelopment (a tactic that uses a weak center to lure an opponent into a trap between two strong wings) in the Morella la Vella cave painting. Once again this seems to read more into the data than can really be supported. Even more fundamental is the problem of definition: What is being called “warfare”? In large part physical anthropologists have adopted the very broad use of the term favored by ethnographers. Thus fighting of the sort seen among hunter-gatherers is usually referred to as war, although it is clearly more akin to the random violence that takes place within a number of species, particularly higher mammals. With the exception of weapons use, the lethal violence between rival chimpanzee groups observed by Jane Goodall bears a remarkable resemblance to the fighting of contemporary hunter-gatherers and, presumably, early humans.

Ants, on the other hand, exemplify the kind of warfare that has been the driving force of our own political history and now poses such a challenge to our survival. The Amazon ants described earlier were not incited randomly by their passions; they were highly organized, in a genetic sense political, and their motives were economic (the acquisition of slaves). All of this requires a complex and stratified social structure, which ants have had for millions of years and which humans have achieved recently. The critical difference is that ants evolved these things genetically, whereas humans clearly learned them. War is a case in point.

For the most part scholars oriented toward political and historical studies have been more attuned to the differences between fighting and warfare; their own professional interests are often the very things that lead them to differentiate between the two. For example, 45 years ago Quincy Wright, although imprecise in his terminology—calling everything from animal and primitive human aggression to imperial aggrandizement “warfare”—was able to see clearly what separated fighting from true war and warned his readers not to carry analogies between them too far. Although historians lacked, until recently, a clear idea of the role of weapons and hunting in early human development, a number of them have correctly and consistently identified the organizational requirements for true warfare, even if they remained somewhat fuzzy as to its motivational basis.

How then did it actually start? The scholarly mainstream dates the inception of true war among humans to somewhere between 7,000 and 9,000 years ago, not as an aberration of the human psyche (as followers of Freud and Jung, such as Sue Mansfield, suggest) but as the culmination of a revolutionary change in economic and social life. Prior to this major transition, humans had been peripatetic beings, going where the game went. However, as early as 20,000 years ago, for reasons that are as yet unclear, scattered groups of humans began settling down and intensifying their efforts at foraging. Shelter and personal possessions no longer had to be portable but could become more substantial and elaborate. Food was stored, and there is evidence of social differentiation.

Several such complex foraging communities have been unearthed from this very early period; they seem to have evolved, collapsed, and disappeared. The primary food they were storing was still meat, which spoils easily, and it seems these societies simply could not perpetuate themselves on this resource base. It is also possible that violence, intramural or from the outside, played a role in their extinction, for the bases of societal conflict—property and politics—were in place in a primitive form.

Somewhat later, groups that had never stopped depending on big game for sustenance began to make the transition from hunting to herding. Though they continued to move as nomads, they now controlled the movement of their food supply, not vice versa. Control, moreover, implied ownership. Thus, flocks were transformed into property to be protected.

True war, however, probably required a more robust economic engine than either early settlement or pastoralism could supply. Agriculture provided it. The roots of agriculture appear to go back 13,000 or 14,000 years, to a few Middle Eastern cultures based on the harvesting of abundant wild grains that could be stored for long periods. Gradually, over the next 3 ,000 or 4,000 years, the deliberate practice of planting and cultivating grains took hold, and as agricultural techniques improved, fertile, well-watered land began to produce regular and substantial surpluses. By degrees, a nexus of property grew up around the agricultural communities. Wealth accumulated, and it fueled the growth not only of a much more complex social structure but of covetousness and the will to power.

War may well have begun, as Jacob Bronowski suggests, when nomads, having learned to steal from one another’s flocks, swept down on the farmers to take their surpluses—a major theme of aggression until at least the time of Genghis Khan. It was the response of the farmers, however, that would provide the major substance for our warlike past. As farmers learned to defend themselves, it became apparent that the more bountiful agrarian economic system imparted certain advantages in terms of resources and time available for martial activities. These could be turned against fellow plant growers to obtain land, women, possessions, and even political dominion.

Archaeologically, these changes are reflected in two ways: the appearance of such weapons as the mace and later the battle-ax, clearly specialized for combat, not hunting; and the introduction of massive walls encircling centers of population. In the latter case, the discovery and subsequent excavation of the fabled walls of Jericho in the mid-1950s revealed that such fortifications were a good deal older (c. 7000 B.C.) and more advanced than anyone had suspected. Moreover, their size (up to 27 feet tall) and sophistication implied the capacity to engineer an equally potent means of attack.

Nor was Jericho unique. Its very early, elaborate fortifications were clearly a reaction to the danger that would later be posed to city dwellers generally by calculated aggression from the outside. Thus around 6300 B.C. the rich and remarkable settlement of Catal Hüyük, in what is now Turkey, employed the interconnected outer walls of its individual structures to produce what is generally regarded as a continuous defensive front. At Hacilar and Mersin, also sites in Turkey dating to the seventh and sixth millennia B.C., this arrangement was supplemented by a strong, separate encircling wall. As time went on, virtually every population center became a Jericho, outer walls and towers being at once the preservers and the price of civilization.

Once plant growers realized the possibilities for gain inherent in organized, premeditated, and economically purposeful aggression, they had only to look to themselves to find the means to create effective fighting forces. The behavorial basis of soldiering had already been established, perhaps less by man’s previous experience with intraspecific combat, which after all was largely individualized, than by the lessons in cooperative mass killing that he had learned as a hunter. As much as anything, hunting had prepared man for war. The two main styles of war until the advent of the gun—close-in combat, exemplified by the phalanx; and long-range combat, conducted by military archery—both had their roots in the Pleistocene chase, the former in the hand-to-tusk spearing of big game and the latter in the shooting of small animals from a distance. Further, it seems likely that the stealth and cooperation required to kill animals effciently was later reflected in the tactics and leadership that would usually spell the difference between victory and defeat in war. It was the cool ruthlessness of the hunt that would help make armies such effective killing instruments, allowing men to commit acts of mass butchery unprecedented except for the slaughter of antelope run off a cliff.

Whether one accepts or rejects Karl Wittfogel’s thesis that the organization of agriculture and irrigation provided the model for military command, it is clear that disciplined, hierarchical fighting forces, once developed, were not only ideal means of aggression but imposing instruments of social control.

So man’s first political agenda was set; he became an imperial ape and a soldier, a conqueror and an organizer. And this, it would seem, is how and why war was born.

Yet we should not forget that man was required to learn his new roles; he was not born into them. It was social innovation, not evolution, that drove the process. War is and always was a cultural phenomenon among humans. What we learned to do, we can choose to stop doing. We may not so choose, but it is possible. Our fate is in our own hands. Technology, particularly nuclear technology, has rendered war, man’s most powerful social institution, obsolete. If we recognize this in time, we will probably remain alive to watch as the ants carry on the tradition. For they have no choice. MHQ

ROBERT L. O’CONNELL is a senior analyst at the U.S. Army Foreign Science and Technology Center in Charlottesville, Virginia. His book Of Arms and Men: A History of War, Weapons, and Aggression is published by Oxford University Press. 

This article originally appeared in the Spring 1989 issue (Vol. 1, No. 3) of MHQ—The Quarterly Journal of Military History with the headline: The Origins of War

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