Neanderthal head injury less common than thought
Comparative analysis finds early modern humans copped concussion as often their evolutionary cousins. Dyani Lewis reports.
A fossil record littered with broken bones and fractured skulls has given Neanderthals a reputation for having led lives full of risk and violence. But that reputation is unfair, according to a fresh analysis of prehistoric knocks to the head.
The study, published in the journal Nature, is the first to compare Neanderthals – thought to be particularly prone to head injury – with members of our own species who lived in Western Eurasia at the same time as our closest known relative.
Katerina Harvati and her colleagues at the University of Tübingen in Germany scoured the scientific record for reports on human and Neanderthal skulls from between 80,000 and 20,000 years ago.
Skulls, which comprise 14 separate bones, are an especially useful record of prehistoric trauma. That’s because wounds heal with only minor bone remodelling, leaving visible scars even after full recovery.
Instead of just looking for skulls with injuries – as previous studies have done – the team gathered data on uninjured skulls as well, so that they could get an idea of how common head trauma was across the population.
In all, the team uncovered records for 114 Neanderthal and 90 Upper Palaeolithic modern human specimens – mostly incomplete skulls with as few as a single cranial bone intact. Nine Neanderthals and 12 Palaeolithic humans had head injuries.
They then crunched the numbers to predict the rate of head trauma in each population.
What they found was that head trauma was no more common in Neanderthals than in Palaeolithic humans.
The rates of injury for both groups are also comparable to estimates for later populations of anatomically modern humans, including both hunter-gatherers and early agriculturalists.
“It’s really exciting work,” says palaeontologist Darren Curnoe from the University of New South Wales, who wasn’t involved in the study. “It challenges the views that we have about Neanderthals – ideas that we've had for a long time.”
Many assumptions about Neanderthal life have been based on little more than case reports of individual skeletons. Reports of blows to the head have led researchers to speculate that Neanderthals lived in violent societies, or that they relied on inferior hunting technologies such as thrusting spears that brought them into close-range confrontations with large prey.
The new data suggest that those speculations may have been unnecessary.
“Our findings refute the hypothesis that Neanderthals were more prone to head injuries than modern humans, contrary to common perception,” explains Harvati.
“The commonly cited Neanderthal behaviours leading to high injury levels, such as violent behavior and inferior hunting capabilities, must be reconsidered.”
Cultural differences have also been invoked to explain why Neanderthals went extinct around 40,000 years ago.
“We've got to come up with different explanations now for why Neanderthals disappeared and we didn't," says Curnoe.
“It looks as though we're beginning to be able to exclude the idea that it comes down to their ecology or the niche they occupied or the way they practiced their hunting and gathering.”
In both Neanderthals and Palaeolithic humans, males were more likely to have a head injury than females, suggesting a similar division of labour in both societies.
One novel finding was that Neanderthal skull injuries were more likely to occur in younger individuals than those of the Palaeolithic humans. This could mean that Neanderthals were more likely to be injured young, or that they were less likely to survive into old age after an injury.
“Overall, however, our results suggest that Neanderthal lifestyles were not more dangerous than those of our ancestors, early modern Europeans,” says Harvati.