Reconstruction
El Sidrón in Asturias holds the remains of a group of Neanderthals who died around 49,000 years ago, and in 2017 their teeth produced an unusually intimate record of what they ate. The method is dental calculus: plaque that mineralises on teeth, trapping DNA from food, from oral bacteria and from anything else that passed through the mouth, then surviving for tens of thousands of years. Sequencing it recovers a signal no bone chemistry can match, because it names individuals rather than averaging populations. The El Sidrón result is a forest diet. Pine nuts, mushrooms and moss appear in the calculus, and no meat was detected in these individuals at all. Set against contemporaries from Spy cave in Belgium, whose calculus records woolly rhinoceros and wild sheep, the contrast is stark: the same species, at broadly the same date, eating entirely differently according to whether they lived in Atlantic forest or on open steppe. That variation is the finding. Neanderthal diet was not one thing, and the specialist-carnivore image built from isotope studies of northern populations does not describe the southern ones. One individual carries something further. They had a dental abscess visible in the jaw and a chronic gastrointestinal pathogen, Enterocytozoon bieneusi, identified in the calculus. In the same plaque are traces of poplar, whose bark and leaves contain salicylic acid, the compound behind aspirin, and of Penicillium, a mould that produces antibiotic compounds. The published interpretation raises self-medication: an individual in pain and with a gut infection consuming exactly the two things that would help. The coincidence is arresting and the caution is necessary. Poplar is common, bark gets chewed, and mould grows on stored or fallen vegetation, so both could arrive in a mouth without any therapeutic intent. Calculus records what entered the mouth, never why. There is also a specific caveat on the moss. A later analysis argued that the moss identification is most likely a database artefact, because the species involved is a laboratory model organism whose genome is heavily over-represented in reference databases, which biases matches toward it. That is a normal hazard of metagenomic identification and it does not undermine the pine nuts, the mushrooms or the medicinal traces, but the moss should be treated as doubtful. What survives all the caveats is the core result: individual-level dietary evidence showing Neanderthals eating according to their landscape rather than to a species-wide script, and at least one of them with the pharmacologically active parts of a willow-family tree in their mouth while suffering from an abscess.
Historical context
Around 49,000 years ago, Neanderthals occupied Europe while modern humans were expanding out of the Near East, and the two overlapped for several thousand years before Neanderthals disappeared. Mousterian tools, fire and hide-working were standard. Northern Iberia held mixed Atlantic woodland with deer, ibex and boar, considerably milder than the mammoth steppe of northern Europe. Neither pottery nor agriculture existed anywhere; every food named here was gathered or hunted wild.
Evidence
Residue chemical
StrongAncient DNA was sequenced directly from mineralised dental calculus of multiple individuals, recovering dietary, microbial and pathogen sequences.
Food identification
ModeratePine nuts and mushrooms are identified from calculus DNA. The moss identification has since been challenged as a probable reference-database artefact and should be treated as doubtful.
Historical interpretation
InterpretivePoplar and Penicillium traces alongside an abscess and a gut pathogen suggest self-medication. Calculus records what entered the mouth, not intent, and both substances could arrive incidentally.
Dating
ModerateThe El Sidrón assemblage is dated to approximately 49,000 years, consistent with the card.
Geographic attribution
StrongThe dietary contrast between forested northern Iberia and the Belgian steppe at Spy is drawn from calculus of individuals at both sites in the same study.
Sources
- 1.Laura S. Weyrich, Sebastian Duchene, Julien Soubrier, et al. (2017). Neanderthal behaviour, diet, and disease inferred from ancient DNA in dental calculus. Nature 544(7650), 357-361. doi:10.1038/nature21674Scientific literature
- 2.bioRxiv preprint (2022). Neanderthals did not likely consume Physcomitrium patens - a model moss species. bioRxiv. www.biorxiv.org/content/10.1101/2022.01.26.47296Scientific literature
Limitations
- moderatefood identification
The moss identified in this study was later argued to be a reference-database artefact, since the species is a laboratory model organism whose genome is over-represented in databases used for matching. Popular accounts repeat the moss finding as established; it should be treated as doubtful.
- moderatefood identification
No meat was detected in the El Sidrón individuals, which is not the same as a meat-free diet. Absence in calculus is weak evidence, and several accounts have escalated this into calling these Neanderthals vegetarian, which the data cannot support.
- moderatehistorical interpretation
Self-medication with poplar and Penicillium is an interpretation of co-occurrence. Calculus records what entered the mouth, never intent, and both substances are common enough to arrive incidentally.
