In 2012 the remains of 27 hunter–gatherers were unearthed in a remote part of Kenya called Nataruk near Lake Turkana—many of whom, based on the startling state of their bony remnants, died horrifically violent deaths. Skulls were bashed in with blunt objects; knees and hands bound and broken. Razor-sharp obsidian spear tips were found lodged in two of the skeletons.

After exhuming and carbon-dating the skeletons, researchers from the University of Cambridge Leverhulme Center for Human Evolutionary Studies have published their findings in this week’s Nature, reporting that the remains are estimated to be from between 9,500 and 10,500 years ago, making it the earliest scientifically dated evidence of organized human violence among scavenging humans. (Scientific American is part of Nature Publishing Group.)

Whereas other recent evidence suggests that hunter–gatherer conflicts resulted in the men being slayed while women and children were assimilated to the victorious group, the winners of this conflict were considerably less discerning. At least eight of the victims were female—including one carrying a six- to nine-month-old fetus—five were children and one was a teenager.

Although the recent discovery is the oldest for hunter–gatherers, it is not the oldest find of large-scale human violence—currently that title goes to remains discovered in the 1960s at the Jebel Sahaba site in Sudan, which could be up to 13,000 years old. Researchers say, however, that although the Sudan site is probably older, the dating methods were not as reliable as the one used for this new study. Also, many of those remains were found in what appeared to be a cemetery and could have accumulated over many years. “The significance of Nataruk lies partly in its early age but particularly in the fact that it is evidence of a single event,” explains professor of human evolution Robert Foley, who co-authored the new paper with his Cambridge colleague evolutionary biologist Marta Mirazón Lahr.

This skeleton was that of a young woman, who was pregnant at the time of her death. She was found in a sitting position, with the hands crossed between her legs. The position of the body suggests that the hands and feet may have been bound.
Illustration by Marta Mirazon Lahr

Foley also points out that the new findings suggest that group violence occurred among people whose way of life was nomadic and often fought for resources as opposed to—as the Jebel Sahaba cemetery implies—an established community where territories and allotment of possessions and properties were more clearly identified “This shows that even under hunter–gatherer conditions, conflicts between groups became serious enough for this level of killing,” Foley says.

His point is significant, given that one school of anthropological thought holds that coordinated conflict, and eventually what we would call warfare, only arose with the settlement of land and a sense of proprietorship over resources. This thinking, as Foley points out, traces back to the idea of the “noble savage” being uncorrupted by civilization, a phrase which first appeared in English in John Dryden's 1672 play The Conquest of Granada and which is often misattributed to 18th-century French philosopher Jean-Jacques Rousseau.

Yet violence predating advances like agriculture is more in line with a perhaps disheartening counterview in anthropology—one echoing English philosopher Thomas Hobbes’s idea that war and violence toward one another is the natural state of mankind—positing that conflict among humans and our predecessors has deep evolutionary roots that exist independently of cultural advance. “This is an important discovery because it provides crucial data to answer a long-standing debate about whether warfare predates agriculture,” comments Luke Glowacki, a Harvard University anthropologist who studies the evolutionary roots of violence. “This new study shows that warfare can and did occur in the absence of agriculture and complex social organization. It fills in important gaps in our understanding of the human propensity for violence and suggests a continuum between chimpanzee raiding and full-blown human warfare.”

Although the recently discovered fallen Africans are thought to have lived a mobile existence, there is evidence that they were at least somewhat situated. Nataruk at the time abutted a fertile lagoon and would have been ripe with valuable resources like water and seafood. Also pottery was found at the site, which among early hunter–gatherers is, as Rutgers University anthropology professor Brian Ferguson points out, “usually associated with increased sedentism, food storage and heightened social complexity. It’s possible that the Lake Turkana victims were ensconced in a particularly productive locale, and those who massacred them came from somewhere much worse off.

“There is probably little doubt that settling down and giving up a nomadic way of life would have intensified the probability of violence between groups,” Foley says. “For most hunter–gatherers, mobility was a strategy for avoiding such conflicts. However, if one looks at chimpanzees we see similar levels of intergroup conflict, and that might be an indication that it has a deeper ancestry in our evolutionary past.”

To this point, Glowacki explains that studies looking at more modern hunter–gathers also suggest that humans probably have some deep-rooted tendency toward violence. “[Early] wars occur even in cases without resource competition,” he says. “In fact, resource abundance rather than competition sometimes contributes to increasing intensity of warfare because individuals are freed from worrying about providing for their basic subsistence needs.”

Foley feels that a contributor to this violent tendency in humans and our ancestors might be, ironically, the same development that allows for altruism and compassion—that is, cooperation. “I can see violent attacks as deriving from the ability of humans to form groups with high levels of solidarity—put simple, between-group rivalry may have come with group coordination and sociality.”

Unfortunately, as Nataruk and other instances of prehistoric group carnage suggest, friendship and ferocity seem to go hand in hand.