© Nikola Solic / ReutersA Neanderthal skull on display at Krapina, Croatia.
The very first Neanderthal to be described in the scientific literature, back in 1856, had an old elbow injury-a fracture that had since healed, but had deformed the bone in the process. Such injuries turned out to be incredibly common. Almost every reasonably complete Neanderthal skeleton that was found during the subsequent century had at least one sign of physical trauma. Some researchers attributed these lesions to fights, others to attacks by predators. But whatever the precise reason, scientists collectively inferred that Neanderthals must have lived short, stressful, and harsh lives.

In 1995, the anthropologists Thomas Berger and Erik Trinkaus cemented that impression by showing that Neanderthal injuries were concentrated around the head and neck. Of 17 skeletons, around 30 percent had signs of cranial trauma-a far higher proportion than in either prehistoric hunter-gatherers or 20th century humans. Only one group showed a similar pattern of fractures-rodeo riders.

"This is not meant to imply that Neanderthals would have met the behavioral qualifications for membership in the Professional Rodeo Cowboys Association," wrote Berger and Trinkaus. Rather, it suggests that they hunted large beasts like mammoths, using spears that were more suitable for thrusting than throwing. They engaged their prey at close range, and had to cling on to wounded, thrashing targets. "Given the tendency of ungulates to react strongly to being impaled, the frequency of head and neck injuries... in the Neanderthals should not be surprising," the duo wrote.

Even then, the duo noted that their conclusions were based on small and possibly unrepresentative samples. And after 17 years, Trinkaus doubled back on his idea completely, noting that later studies had found similar injury patterns among the Pleistocene humans who lived alongside Neanderthals. The rodeo rider hypothesis, he said, should be "further qualified if not simply retracted." (Trinkaus declined to be interviewed for this story.)

But the hypothesis, and the broader notion of highly traumatized Neanderthals, clung to the popular consciousness as tenaciously as an imagined Neanderthal to a mammoth's back. Some researchers have argued that their frequently broken bodies would have stopped Neanderthals from effectively passing technological skills to each other. Others have argued that they could only have survived their common wounds through medical savvy.

But in a new study-the largest of its kind-Katerina Harvati and her colleagues at the University of Tübingen have shown that head injuries really weren't that common in Neanderthals, and certainly no more so than in contemporaneous Homo sapiens. "This implies that Neanderthal trauma does not require its own special explanations, and that risk and danger were as much a part of the life of Neanderthals as they were of our own evolutionary past," writes Marta Mirazon Lahr from the University of Cambridge, in an accompanying editorial.

"The [high frequency of] head trauma has been used to argue that they were more violent with each other, or hunted in a more particular way," says Harvati. "We've taken away one piece of evidence for that. It's important to re-examine our assumptions about their behaviors."

Other studies had come to similar conclusions, but none have looked at such a large number of skeletons, says Rebecca Wragg Sykes, an archeologist from the University of Bordeaux who studies Neanderthals. "It really [helps] to push back against the stubborn image of Neanderthals as having massively battered bodies," she says. That image persisted partly because "it seemed to be a believable reason why we were supposedly more successful. Having clear data to disprove that, based on a really good sample size, [adds to] the growing view that there were many similarities in behavior between the two species."

This study adds to the continuing image makeover of Neanderthals, which had long been pictured as brutish and unsophisticated. It's now clear that they made tools, used fire, made art, buried their dead, and perhaps even had language.

By combing through previous studies, Harvati's colleague Judith Beier compared the skulls of 114 Neanderthals and 90 modern humans, all of whom lived in Europe and Asia between 20,000 and 80,000 years ago. (The term "modern human" here refers to Homo sapiens, rather than present-day people.) She estimated that between 4 and 33 percent of Neanderthals would have had some kind of head injury, compared with 2 to 34 percent of contemporaneous modern humans.

These ranges are large because Beier tried to account for how whether the fossils were found, how well-preserved they were, and other factors that could influence the odds of detecting old injuries at all. ("You can't just look at the raw frequencies," she says.) But it's clear that earlier estimates of head injuries among 30 to 40 percent of Neanderthals represent the very extreme of what Beier thinks was likely. It's also clear that Neanderthals and modern humans were equally likely to severely bonk their heads.

Beier found that in both groups, males were more likely to have head injuries than females - a pattern that still exists among today's humans. Perhaps they were more likely to hunt, fight, or get into accidents. More intriguingly, the team also found that Neanderthals were more likely to accrue head trauma before the age of 30, while modern humans experienced such injuries more evenly throughout their lives. That difference is harder to explain. "We struggled with it a lot," says Harvati.

One possibility, she says, is that Neanderthal youths were just more likely to get knocked in the head than similarly aged modern humans. It's also possible that modern humans were better at taking care of head injuries, while Neanderthals were more likely to die early from the lingering effects of their wounds. And Wragg Sykes adds that the pattern might reflect differences in how the two groups treated their dead, which in turn would affect how likely we are to find their injured remains.

She adds that the team's study wasn't comprehensive. They didn't include any children under the age of 12. They also omitted the oldest specimens from both groups, including the numerous 125,000-year-old Neanderthals from Krapina, Croatia, or the Homo sapiens skulls from Skhul and Qafzeh in Israel, which were between 80,000 and 120,000 years old. And they only looked at skull injuries, rather than those affecting other parts of the body. ("It became clear very quickly that we couldn't look at everything," says Harvati. "It would have taken an extraordinary amount of time, so we had to limit ourselves.")

"As our samples grow and our research methods become more sophisticated, the gap between them and us is shrinking," Wragg Sykes said.