Scientific Method / Science & Exploration

Fossilized poop shows that Neanderthals ate their veggies

Fecal-matter samples in question date back around 50,000 years.

Did the Neanderthals eat their vegetables? The answer to this question lies not in the tea leaves but in the poop.

It has long been assumed that the extinct humans were purely carnivorous and that the dietary differences from anatomically modern humans might have been responsible for their demise. But new evidence suggests that as well as enjoying a high meat intake, Neanderthals also had a significant plant element as part of their diets.

Researchers from MIT and the University of La Laguna made the discovery after examining the makeup of samples of what may be the oldest-known fecal matter, which date back about 50,000 years. Extracted from a Middle Paleolithic site in El Salt in Spain, the samples were examined for biomarkers that could be analyzed to identify dietary sources.

As has long been suspected, the Neanderthal diet consisted predominantly of meat, as indicated by high proportions of one particular biomarker called coprostanol in the fecal matter. Coprostanol is formed from the bacterial reduction of cholesterol, and the bacteria required to perform this conversion is still present in the guts of modern humans today.

Another biomarker, however, has revealed compounds—known as phytosterol metabolites—that are often found in plants. This compound is uniquely formed in the intestinal tracts of higher mammals during the ingestion of plants. This is considered to be the first direct evidence that Neanderthals consumed plants and animals and were therefore omnivorous. Previously, analysis of dental calculus revealed microfossils and organic residues trapped in Neanderthal teeth, but these findings were restricted to only a small part of the Eurasian region where Neanderthals lived.

Further studies using the same biomarker approach will hopefully clarify the nature, role, and proportion of plant consumption in the Neanderthal diet. Now that it has been established that Neanderthals have at least some of the same stomach bacteria that we do—the bacteria converting cholesterol to coprostanol—the study's authors also hope it will help them to gain some insight into the evolution of the human digestive system. This has been difficult in the past given that there is no fossil record indicating soft tissue preservation, but the biomarker method will allow the researchers to understand the difference between modern and ancient gut microbiota.

The full study, published in journal PLOS One, can be accessed here.

This story originally appeared on Wired UK.

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