Enlarge / The jaw of the El Sidron individual found to be consuming poplar and Penicillium-containing vegetation.
Paleoanthropology Group MNCN-CSIC
Around 50,000 years ago in Spain, a Neanderthal had a toothache and popped the botanical version of an aspirin. Maybe. Although it's far from clear-cut, theres evidence from old teeth that hints at the possibility.
It's part of a study of Neanderthal diet, courtesy of their poor dental hygiene. Published in Nature, an analysis of preserved dental plaque from three different Neanderthals provides an intriguing glimpse into what theyput in their mouths. According to the authors, the analysis points to regionally varied diets and suggests possible medicinal plant use.
But some of the DNA evidence is a little strange, suggesting evidence of species where they really shouldnt have been 50,000 years ago. There are some good explanations for why this could happen, but, like most exciting results, drawing conclusions from the evidence demands a little caution.
The stereotypical picture of Neanderthals paints them as hunting the woolly mammoth. Theres evidence to back up a Neanderthal diet as carnivorous as polar bears or wolves, write the researchers: archaeological and chemical data suggest mealsheavy in large herbivores like reindeer, woolly mammoth, and woolly rhinoceros.
But Neanderthal teeth tell a more nuanced story. Previous research has found that the wear patterns on their teeth suggest a varied diet with regional differences. And dental plaque has been used before to analyze the starches and proteins that were preserved in the plaque. These analyses suggest that Neanderthals were eating many plants, possibly including medicinal ones.
Butdental plaque canpreserve more than simple chemicals; genetic material from the food can be encased init. This allowed a team of researchers, led by Laura Weyrich at the University of Adelaide, to get an incredibly detailed look at what plant and animal species three individual Neanderthals had been eating. Two were from El Sidrn Cave in Spain, including thepotential aspirin-popper, while one was from Spy Cave in Belgium.
The results add to previous evidence suggesting that the Neanderthal diet was actually many different things, depending on where the Neanderthals in question lived. The Belgian followed the meat-heavy pattern, with genetic material from woolly rhinoceros, mushrooms, and wild sheep showing up in the dental plaque. Mammoth, reindeer, rhinoceros and horse bones in the cave tell the same story as the dental plaque: these were hunters.
The Spanish Neanderthals, on the other hand, seemed to eat largely mushrooms, pine nuts, and mossthe kinds of food youd get from foraging in a forest. One of them had a dental abscess, and this individuals teeth came up with the genome of a poplar tree that has high levels of salicylic acid, aspirins active ingredient.
Heres where it gets a little slippery. The species identified, Populus trichocarpa, is actually native to North America. It wouldnt have been present in Europe 50,000 years ago, says Quentin Cronk, a botanist with an interest in the poplar genome, who wasnt an author on this paper. But it does have a pretty close relative in Europe, Populus nigra.
Whats going on here, says ancient DNA researcherHannes Schroeder, could be one of two things. The first possibility is contamination. The authors were watching out for this, though, and eliminated the data from two other Neanderthals because there was evidence of contamination. The DNA they ended up analyzing showed all the signs of being properly ancient. The other possibility is that, because ancient DNA is degraded and its possible to analyze only short strands of it, the strands left in the dental plaque matched more than one poplar species.
As it happens, Populus trichocarpa has the best genome data available amongthe poplars. All the other species of tree and mushroom identifiedincluding another oddity, the Korean pinehave good genome-sequencing data available, too. This suggests that the little bits of DNA matched up with the genomes available in genetic databases and just locked onto the species that happened to be in the databases because they didnt have enough data in them to differentiate between different species.
The most likely explanation of this issue is that the reads come from a European species of Populus that is not adequately represented in current sequence databases, says Daniel Huson, one of the authors of the paper. Cronk agrees that this is likely, as does Schroeder.
Its a bit strange for the authors to have pinpointed a single, impossible species, rather than identifyingthe genetic remains as belonging to the Populusgenus. It doesnt cause too much of a problem for the evidence of what Neanderthals were eating, thoughmushrooms are mushrooms. A difference in species doesnt really change the evidence that these people were eating like vegans rather than Texans.
As for the medicinal claim, theres also some evidence of Populus nigra having medicinal properties. Whether or not the Neanderthal knew what these properties were while chowing down on poplar is a different, and possibly unanswerable, question. Some other primate species seem to do this, so it might not be as far-fetched as it seems.
For Schroeder, the evidencedoesn't seem likeespecially solid ground for a big claim like medicinal use. But Keith Dobney, one of the authors on the paper, thinks it all lines up so well that it invites the interpretation of medicinal use. The abscessed individual also had bacteria associated with diarrhea, as well as evidence of the antibiotic Penicillium mould, and it just seems a bit of a strange coincidence that we have one individual with all these things, he says.
With different diets come different oral bacterial cultures. You eat a lot of meat, you get a lot of meat-digesting bacteria in your mouth. Weyrich and her team compared the Neanderthal oral bacteria to a modern human and a group of ancient humans from different cultures.
They found that there were different groupings of oral microbiomes: the SpanishNeanderthals grouped with chimpanzees and ancient African gatherers, in what the researchers called a forager-gatherer group with a largely vegetarian diet. The Belgian Neanderthal grouped more closely with the typical meat-heavy hunter-gatherer diet. Amodern human and early agriculturalist human also had different profiles.
The result helps us understand modern human oral microbiomes in context, says Dobney. Our current food-related health problems, like obesity, didnt happen in a vacuum: it hasnt happened overnight; its part of the journey that weve been on for thousands of years. Major cultural changes like the beginnings of agriculture are still impacting our health today.
As for Neanderthals, he hopes evidence of theirimportant place in our own historyin terms of behavior, genome, and microbiomecan help end the common perception of them asthese knuckle-dragging cavemen able to do not much more than bring down the odd bison here and there. The evidence is pointing toward varied behavior across the Neanderthals, and were starting to be able to get closer to inferences about the sophistication of their behavior and culture.
Nature, 2016. DOI: doi:10.1038/nature21674 (About DOIs).
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Neanderthal teeth tell tales of diet and medicine - Ars Technica
