Food rots, but diet leaves fingerprints. Bone chemistry, the wear on teeth, the tartar stuck to them, and cut marks on prey let scientists reconstruct what extinct humans ate — sometimes meal by meal.
How can anyone know what a Neanderthal had for dinner 50,000 years ago? Meals leave no obvious trace — and yet a whole toolkit of methods lets researchers rebuild ancient diets with real confidence. Here is how the detective work is done.
Four ways to read a lost meal
| Method | What it reveals |
|---|---|
| Stable isotopes | Ratios of carbon and nitrogen in bone show trophic level and whether food came from plants, meat or the sea |
| Dental microwear | Microscopic pits and scratches on teeth distinguish hard, brittle foods from tough, fibrous ones |
| Dental calculus | Hardened tartar traps starch grains, plant silica, and even ancient DNA and proteins |
| Cut marks & coprolites | Butchery marks on prey bones and fossilised faeces record meat-eating directly |
The chemistry of bone
As the saying goes, you are what you eat — right down to your atoms. The ratio of nitrogen isotopes rises at each step up the food chain, so a bone rich in heavy nitrogen signals a heavy meat diet. Early isotope studies placed Neanderthals alongside top carnivores like wolves and hyenas.
The tartar time capsule
That carnivore picture turned out to be too simple. When researchers examined dental calculus — the fossilised plaque on ancient teeth — they found starch grains from cooked plants, seeds and tubers lodged in Neanderthal tartar. At El Sidrón in Spain the tartar even preserved compounds from bitter plants like yarrow and chamomile, hinting that Neanderthals may have self-medicated. Tartar has since yielded entire ancient oral microbiomes.
Microwear and butchery
The wear on a tooth’s surface records the last meals of a life: fine scratches point to tough leaves and meat, deep pits to hard nuts and grit. Meanwhile, stone-tool cut marks on animal bones, and the way bones were smashed for marrow, show exactly which animals were butchered and how. Occasionally, fossil faeces (coprolites) preserve the evidence directly.
Limits and surprises
Every method is partial. Isotopes average years of diet and can miss plants; microwear captures only the final days; calculus preserves some foods better than others. Used together, though, they converge — and they keep overturning the old caricature of Stone Age people as pure meat-eaters.
Why it matters
Diet drove human evolution: a richer, meatier and later cooked diet is closely tied to our expanding brains and shrinking guts. Knowing what our relatives ate — and how flexibly — is central to understanding what made us human. See also when humans learned to control fire.
Curious how we date all these finds? See the methods behind every date on this site.
Read how fossils are dated →Frequently asked questions
How do scientists know what cavemen ate?
By combining several lines of evidence: the chemistry (isotopes) of bone, the microscopic wear on teeth, the food trapped in hardened dental tartar, and cut marks on butchered animal bones.
Were Neanderthals pure carnivores?
No. Isotopes suggested a very meat-heavy diet, but dental tartar revealed cooked plants, seeds and tubers as well, showing Neanderthals were flexible omnivores rather than obligate carnivores.
What is dental calculus?
Dental calculus is hardened plaque — tartar — on teeth. It traps starch grains, plant silica, microbes, and even ancient DNA and proteins, making it a remarkable time capsule of ancient diet and health.
- Henry, A. G., Brooks, A. S. & Piperno, D. R. (2011). 'Microfossils in calculus demonstrate consumption of plants and cooked foods in Neanderthal diets.' PNAS 108. pnas.org
- Richards, M. P. & Trinkaus, E. (2009). 'Isotopic evidence for the diets of European Neanderthals and early modern humans.' PNAS 106. pnas.org
- Weyrich, L. S. et al. (2017). 'Neanderthal behaviour, diet, and disease inferred from ancient DNA in dental calculus.' Nature 544. nature.com