Belgian Neandertals dined on woolly rhinos with a side of mushrooms, whereas their Spanish counterparts feasted on pine nuts and forest moss—and may have even experimented with natural painkillers and antibiotics. That’s the conclusion of the first study to analyze genetic material trapped in the plaque on fossil Neandertal teeth—the same stuff that sends us to the dentist.
The new findings are “very exciting, a whole new layer of evidence that Neandertals’ diets were varied,” says Amanda Henry, a paleoanthropologist at Leiden University in the Netherlands, who was not involved in the work. “Neandertals weren’t just consuming things for calories or for taste,” she says, but instead may have been taking advantage of the medicinal properties of certain plants and bacterial foodstuffs.
As dental plaque or calculus forms, it often traps tiny bits of food. Because Neandertals weren’t known to floss, Laura Weyrich, a paleomicrobiologist at the University of Adelaide in Australia, wondered whether she could study the material for clues to the diets of our ancient relatives.
Her team started with teeth and jaw fossils from Spy cave in Belgium, El Sidrón cave in Spain, and an Italian cave known as Breuil Grotta—all well-studied sites where Neandertal remains have been found. Calculus on the fossils from Spy cave included DNA similar to that of modern rhinoceros and sheep, suggesting that Neandertals who lived there about 36,000 years ago ate woolly rhinoceros and mouflon, a type of wild sheep. The researchers also detected DNA similar to that of the edible gray shag mushroom Coprinopsis cinerea, they report online today in Nature.
Those results back up previous archaeological studies that unearthed the bones of woolly rhinos and other large prey in Spy cave, Weyrich says. Although the remains of mouflon haven’t yet been found there, the creatures were widespread throughout Europe at the time, she notes.
In contrast, the two fossils analyzed from El Sidrón—which have been dated to about 48,000 years ago—yielded no DNA from large animals. Instead, they contained genetic sequences consistent with pine nuts, forest moss, and edible mushrooms. Tellingly, scientists have suggested the area around El Sidrón was densely forested at the time, whereas Belgium about 36,000 years ago hosted a treeless steppe.
Previous studies of microscopic wear patterns on Neandertal teeth from various locations, among others, had suggested the extinct hominins’ diets varied by region and included both meat and various plant material. But Henry also cautions that the new techniques shouldn’t be relied on by themselves, because studies of living humans have shown that not all foods get preserved in dental calculus. “Whether calculus is preserving the remains of a last supper or a long-term dietary average, we don’t know,” she adds.
“This is a very interesting paper,” says Hervé Bocherens, a paleobiologist at the University of Tübingen in Germany. It’s always good to have new analytical techniques that complement others already in use, “because each one has its limitations,” he notes. For example, mushrooms don’t often get preserved in the archaeological record.
Two findings from one of the El Sidrón cave fossils are especially interesting, Weyrich says. The team’s DNA analysis reveals traces of poplar (which contains the natural painkiller salicylic acid, the active ingredient in aspirin) and of the antibiotic-producing Penicillium fungus (often found on moldy vegetation), both of which the individual may have been using to self-medicate a dental abscess, the researchers propose. The other fossils the team studied don’t include such DNA sequences, Weyrich says.
The notion of self-medication in Neandertals isn’t new: In 2012, researchers reported a chemical analysis of dental plaque from five Neandertals unearthed at El Sidrón that found evidence of bitter-tasting compounds from plants like yarrow and chamomile. These plants have no nutritional value, the scientists noted, so they may have been used as appetite suppressants or may have been considered to have some sort of medicinal value.
*Correction, 9 March, 10:04 a.m.: This article has been updated to reflect the fact that Penicillium is a fungus and not a bacterium.