Neanderthals went to the dentist (really)

For much of the modern era, “Neanderthal” has served as shorthand for brutishness and ineptitude. Yet mounting archaeological evidence suggests a rather more refined species: one that buried its dead, tended to injured companions and adapted with remarkable success to the rigours of Ice Age Europe.

Many researchers still draw a line between their behaviour and that of modern humans, arguing that they lacked the technical sophistication to perform something as complex as surgery. Now a battered tooth from a cave in southern Siberia, described in the journal PLOS one by Alisa Zubova, Lydia Zotkina and Ksenia Kolobova at the Russian Academy of Sciences, is forcing a rethink.

The tooth in question is a 59,000-year-old molar from an adult Neanderthal. It was discovered in 2016 in Chagyrskaya Cave in the Russian stretch of the Altai Mountains by Dr Kolobova’s team and, like many ancient teeth, it is heavily worn down from years of chewing on tough, gritty food. No other skeletal remains of its owner have been found. What is noteworthy about the tooth is that it has a large hollow on the chewing surface that reaches deep into its centre, where nerves and blood vessels would have been.

At first glance, the hollow looks like the site of a dental infection (or cavity) that would ultimately have proved lethal. But when Dr Zubova and her team looked closer, they realised its owner probably escaped this fate. Microscope images and CT scans revealed grooves and fine striations on the hole’s walls that looked as if they had been made through the repeated rotation of some sort of pointed tool. To their astonishment, this suggested that a Neanderthal had intentionally drilled into the tooth to scoop out infected tissue. Could stone tools alone have been up to the task? Dr Zubova turned to Dr Zotkina, an experimental archaeologist, to find out.

The question of which stone to use was easy to answer: small and sharp tools made of a quartz-like material known as jasper have previously been found in Chagyrskaya Cave. Dr Zotkina consequently worked with her team to build similar tools and then use them to drill into sample teeth. They found that repetitive rotational motions with the jasper were enough to produce markings on teeth in less than an hour. What’s more, the markings they left were strikingly similar to those found on the Neanderthal tooth. This was fossil evidence of dentistry taking place 59,000 years ago, a tooth-aching 45,000 years before modern humans are known to have been engaging in such activities.

Nor does the story stop at the drilling. The margins of the hollow show signs of having been smoothed by subsequent chewing activity. This means that the patient not only survived the procedure but then went on to chew enough food over the course of time to cause the drill site to get worn down. Moreover, the sides of the molar also show signs of “tooth-picking”, whereby the repeated insertion of a narrow object led to grooves forming between the molar and other teeth. Whether this was done before or after the dental procedure is hard to tell, but was probably done to relieve gum irritation. Such behaviour has been documented in earlier human relatives and even in Japanese macaques.

This dental discovery adds valuable detail to the picture of Neanderthal life. For one thing, say the authors, it shows they must have had fine motor control. More important, it suggests that they would have understood the importance of enduring some immediate (and excruciating) pain to reduce the chance of death. Such a calculation would have been impossible without causal reasoning, an attribute whose presence among Neanderthals has long been debated. This finding helps to bring that debate to a close.

“It’s pretty exciting to see such ancient evidence of a medical procedure as complex as this,” says Daniel Lieberman, an evolutionary biologist at Harvard University. “Sometimes I joke when I’m teaching that humans are the only species that would ever willingly go to a dentist. Now,” he adds, “I’ll have to revise my quip.” ■