Neanderthal remains found in El Sidrón Cave (Image: CSIC Comunicación) Neanderthal remains found in El Sidrón Cave (Image: CSIC Comunicación) Microscopic starch granules embedded in Neanderthal teeth (Image: Karen Hardy/ Naturwissenschaften) Researchers working in El Sidrón Cave (Image: CSIC Comunicación) Advertisement

The tartar on Neanderthal teeth has a tale to tell. The chemicals and food fragments it contains reveal that our close relations huddled around fires to cook and consume plants – including some with medicinal properties. The find is the earliest direct evidence of self-medication in prehistory.

Despite their reputed taste for flesh, we now know that at least some Neanderthals enjoyed a more varied diet. The latest evidence comes from an analysis of 50,000-year-old Neanderthal teeth from the El Sidrón site in northern Spain.

Karen Hardy at ICREA, the Catalan Institution for Research and Advanced Studies in Barcelona, working with Stephen Buckley at the University of York, UK, and colleagues, used a scalpel to scrape tartar off the teeth of five Neanderthals. They chemically analysed some of the tartar samples, and examined others using an electron microscope.

Smoke signals

The microscope revealed cracked starch granules, which suggests the Neanderthals roasted plants before eating them. More evidence for the importance of fire was found in the chemicals within the tartar: there were aromatic hydrocarbons and phenols, which are associated with wood smoke.

Unexpectedly, there were few lipids or proteins in the tartar, suggesting the Neanderthals of El Sidrón ate little meat. However, one Neanderthal consumed yarrow, a natural astringent, and camomile, an anti-inflammatory.

“It’s very surprising that the plants we were able to securely identify were those with a bitter taste and no nutritional qualities – but known medicinal properties,” says Hardy. Neanderthals were apparently able to select plants for medical use, she says.

Non-human primates today are known to self-medicate, so the discovery is not unexpected, but finding strong evidence of the practice in prehistory is a challenge, says Hardy.

Amanda Henry at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, agrees. She says there have been hints since the 1970s that Neanderthals had medicinal know-how, but nothing as strong as the evidence from Neanderthal tartar. “To my knowledge this is the first direct evidence of self-medication,” she says.

Veg out

The finding also adds to the evidence of the importance of plants in Neanderthal diets. In 2010, Henry found starch granules and other plant microfossils in Neanderthal tartar from specimens found in Iraq and Belgium, suggesting they ate plants. The nature of preservation indicated the food had been baked or boiled in water rather than roasted (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1016868108).

Erik Trinkaus at Washington University in St Louis, Missouri, and Michael Richards at the Max Planck Institute for Evolutionary Anthropology recently completed an isotopic analysis of Neanderthal bone collagen. Their data suggested the hominins generally got most of their protein from meat.

However, Trinkaus says the new results do not contradict this finding. “[Our analysis] says nothing about their consumption of plant foods or where they got most of their calories from,” he says. “The work of Hardy, Henry and others has documented substantial plant food in the Neanderthal diet, and one would of course expect more in warmer climates.”

It is also possible that meat in the Neanderthal diet has simply failed to leave a signal in the tartar, says Katerina Harvati at Tübingen University in Germany.

The new El Sidrón findings help to paint a picture of everyday Neanderthal life, says Hardy. “The identification of wood smoke is very exciting as it allows us to personalise and bring to life an individual event in which a person might be sitting beside a fire, cooking and eating – and administering medicating plants.”

That peaceful image clashes starkly with another image typically associated with the Neanderthals of El Sidrón. An earlier analysis of Neanderthal teeth from the site by some members of the El Sidrón team suggests the small population experienced periods of nutritional stress. Cut marks on Neanderthal bones from the site suggest many members of the group were cannibalised after death.

Journal reference: Naturwissenschaften, DOI: 10.1007/s00114-012-0942-0