"These human remains record the intentional killing of a small band of foragers with no deliberate burial, and provide unique evidence that warfare was part of the repertoire of inter-group relations among some prehistoric hunter-gatherers," lead author Marta Mirazon Lahr of the University of Cambridge said in a statement.
The remains show signs of arrow wounds and blunt force trauma. One female skeleton paints a particularly jarring picture: Her hands, chest and knees all show signs of fracturing from blunt force trauma. The researchers believe her hands were bound when she died. Nearby, another woman – one who was pregnant – died with her hands and feet bound.
Several of the skeletons were found with the obsidian weapons that may have killed them. Because obsidian tools aren't particularly common in archeological sites from this exact time and place, the researchers write that this may be a sign that the killers came from a different neighborhood.
It seems clear that these remains are the result of some kind of massacre – something different from the interpersonal violence that's surely as old as humanity itself. But does that mean humans were engaging in war 10,000 years ago? It depends on your definition of warfare. The remains have pushed back our earliest evidence of group conflict between humans, but is that all it takes to make "war"? Previously, some scientists had argued that it took cities, farms and industry to incite true war. But these new findings suggest that the resources and squabbles of hunter-gatherer society may have caused groups to turn on one another.
"I’ve no doubt it is in our biology to be aggressive and lethal, just as it is to be deeply caring and loving," co-author Robert Foley said in a statement. "A lot of what we understand about human evolutionary biology suggests these are two sides of the same coin."
It's also possible that the attack served in part to capture some members of the group, and that the individuals left for dead were those who put up a fight or were too young or old to be of any use. Only six children were found in the mass grave, all of them next to the women, and none of them were teenagers. "Whether [the teenagers] managed to escape, or were taken, we will never know," Miraozn Lahr told Reuters.