Researchers have uncovered evidence of a behavior never seen before in ancient hunter-gatherers: the mounting of decapitated heads onto stakes. Displaying decapitated heads on wooden stakes is something you might expect from the Middle Ages, but as a new paper published in the journal Antiquity shows, it’s a practice that goes back much further in time than we thought. And in fact, the discovery is the first evidence of this behavior among Mesolithic hunter-gatherers, who aren’t known for dramatic displays of this sort. The researchers who found the skulls are at a loss to explain why these ancient Europeans would have mounted them on posts, but the reason may not be as sinister as it appears.

Researchers from Stockholm University and the Cultural Heritage Foundation found the skulls at the bottom of what was once a lake, at the Kanaljorden excavation site in Sweden near the Motala Ström river. The human remains, found at an 8,000-year-old burial site, were uncovered back in 2011, and the details of the scientific analysis were finally published. This Mesolithic site has been under investigation since 2009, with archaeologists pulling up butchered animal bones, tools fashioned from antlers, wooden stakes, and bits of human skull. The ancient Scandinavians who used to live at the site survived by hunting, fishing, and gathering. Due to the poor archaeological record, scientists know very little about the sociocultural aspects of these people.
Swedish archaeologists found the remains of 10 individuals—nine adults and one infant— deliberately placed atop a densely packed layer of large stones. One of the adult males was older, probably in his fifties when he died. Two were young, somewhere between the ages of 20 to 35. Two were identified as female and four as male. The nearly-complete skeleton of the infant suggests it was either stillborn or died shortly after birth.


All of the adult skulls exhibited signs of blunt force trauma some time prior to death. The majority of these injuries were near the top of the head, above the so-called hat brim line. For some reason, the injuries varied according to sex; the two females had injuries at the back and right side of their heads, while the males displayed signs of a single traumatic event to the top of the head or face. Some of the skulls showed signs of healing. None of the skulls were found with mandibles, which the researchers suspect had something to do with ancient burial practices. They don’t know what weapons were used to inflict this damage, and the wounds couldn’t be tied to cause of death—but the injuries weren’t subtle.

"Though the lesions were not lethal, they must have affected the individuals—induced pain, bleeding, and a risk of secondary infections,” study author and Stockholm University archeologist Anna Kjellström said. “Furthermore, even less severe head trauma may cause loss of consciousness, internal bleeding, or even permanent mental impairment.”

To the surprise of the researchers, three of the male skulls exhibited signs of sharp force trauma after death. Incredibly—and after 8,000 years—the well-preserved remains of wooden stakes were found dislodged inside two of the skulls, suggesting they had been mounted prior to being deposited in the lake. In one case, the wooden spike was still sticking out of the cranium. The stakes were inserted through the large oval opening at the bottom of the skull (foramen magnum) reaching through the top of the skull.

In all, the researchers managed to uncover 400 intact and fragmentary bits of wooden stakes at the site, some of which may have been used to mount objects that have since fallen off. Other stakes may have been used for construction purposes, such as partitions or fences.

So what can account for all of this? No conclusions have so far been made.

To be fair, the researchers did posit some explanations, but they weren’t willing to commit to a particular interpretation. The sample size is way too small, and because this is literally the first case of its kind among Mesolithic humans, the scientists had nothing to compare it to.

The blunt force trauma injuries, say the researchers, may have happened by accident (very unlikely given the specificity and recurrence of the injuries), interpersonal violence, forced abduction, spousal abuse, warfare, or socially sanctioned non-lethal violence. Because these injuries were differentiated by sex, the victims may have been part of a stigmatized group. One possibility is gender-related violence—a society where men and women were treated or behaved differently from each other. Or these people were slaves—a highly unlikely scenario, say the researchers, as that’s unheard of among hunter-gatherers who lacked the resources (and possibly motivations) to maintain a slave class. More realistically, the injuries were inflicted during raiding and warfare. As the authors write:
“The gender-related trauma pattern... is reminiscent of patterns observed among North American prehistoric hunter-gatherers, which have been interpreted as a result of different roles and behaviour in combat. This could be associated with how individuals of different gender and age may play different roles in a combat situation.”

Finally, the blunt force trauma injuries could have been inflicted for cultural reasons, as hard as that is to believe.

“We have not a found any clear indications that suggest that these individuals had another affinity or social status than people buried close to this site,” Kjellström said. “We want to point out that the injuries may not necessarily have occurred under hostile actions. For example, there are anthropological descriptions where lesions on participants occur from ritual ceremonies. This complicates the interpretation of who these individuals were.”

As for the handling of the bodies after death and the mounting of heads on wooden stakes, that’s definitely weird. Mesolithic hunter-gatherers are not known to remove body parts like this; their grave sites show a respect for bodily integrity after death. That said, groups that appeared much later in history did decapitate their enemies, sometimes using the skulls of the vanquished as a trophy or warning. Historical examples include European colonists mounting the skulls of murdered indigenous peoples, or indigenous peoples using skulls in both burial rituals and as trophy displays. It’s not clear what the context was in this case. All we know is that, for whatever reason, these heads were mounted on the stakes, left there for a relatively short period of time, and then deliberately laid to rest in the shallow lakebed on the stones.

“The fact that two crania were mounted suggests that they have been on display, in the lake or elsewhere,” said Kjellström. In general, skulls without jaws were chosen for the display. “Since we did not find any sharp trauma showing active attempts to separate the lower jaw from the skulls, this indicates that the individuals much likely were buried in another place before the depositions... One interpretation could be that this is an alternative funeral act.”
We won’t know more until further research is done, and until more bones and artifacts are uncovered. But one thing’s for sure—we’ll never look at hunter-gatherers the same way again.