Biology
Neanderthal Dental Calculus and Microbiome Evidence of Dietary Flexibility
Quick fact
Analysis of Neanderthal dental calculus from a site in Spain revealed DNA of poplar, which contains salicylic acid (the active ingredient in aspirin), and Penicillium fungus—suggesting self-medication with natural painkillers and antibiotics some 50,000 years ago.
Why this is interesting
Have you ever thought your toothbrush does more than just clean your teeth? For Neanderthals who never brushed, the plaque that hardened on their teeth has become a treasure trove—a time capsule of what they ate, what microbes lived in their mouths, and even how they treated illness. What would we find in yours?
Read the full explanation
Understanding Neanderthal Dental Calculus and Microbiome Evidence of Dietary Flexibility
Imagine plaque on your teeth: a sticky biofilm of bacteria and food debris. If you never brush, that plaque hardens into tartar (dental calculus), which is mineralized and incredibly durable. Over tens of thousands of years, while bones decay, calculus can persist, effectively locking in a snapshot of the oral microbiome and the food particles that got trapped. Scientists can grind up these ancient specks and extract DNA from the bacteria and plants that were present. They can also look for microscopic plant remains called phytoliths and starch grains. By comparing these genetic and microfossil fingerprints to modern databases, they can reconstruct an individual Neanderthal's last meals and even their general dietary habits. This provides a direct, molecular 'diary' of what that person ate and what bacteria thrived in their mouth.
A deeper explanation
The key mechanism behind this is the process of fossilization at a molecular level. Dental calculus is composed of calcium phosphate minerals (hydroxyapatite) that precipitate from saliva and accumulate on teeth. Once mineralized, it forms a protective seal that shields DNA from water and microbial degradation. The biofilm architecture also incorporates polysaccharides and proteins that bind and stabilize nucleic acids. Over time, the calculus becomes a sort of 'microbial corpse'—a hard resin that preserves both the microbes themselves and any plant or animal DNA they encountered. Scientists use high-throughput sequencing to read the ancient DNA, carefully filtering out contaminating modern DNA by checking for characteristic damage patterns. By comparing the microbial taxonomy and the plant/animal DNA recovered, they can infer dietary breadth. The finding of DNA from plants like poplar, and microfossils of mushrooms, nuts, and tubers, contradicts the old 'meat specialist' hypothesis. Instead, it reveals a flexible omnivorous strategy, and even the ability to select plants for their pharmacological properties. This matters because it shows that Neanderthals were not simply brute hunters, but adaptively resourceful, capable of exploiting a wide range of environments and food sources.