The Trouble with Reconstructing Ancient Diets

Archaeologists once reconstructed prehistoric diets from what survived in the ground, which meant, in practice, from bones. The picture that emerged was overwhelmingly one of meat. It took a long time for the discipline to accept that this said less about what people ate than about what rots.

[A] Chemical analysis of tooth enamel has since made a more balanced account possible, because the ratio of carbon isotopes laid down during childhood reflects the plants at the base of the food chain, whether they were eaten directly or by way of an animal. [B] Sites where the bone assemblage suggested a diet of large game have yielded enamel values pointing to a heavy reliance on plants. [C] The correction has not been uniform, and a few coastal sites turn out to have been as carnivorous as the old accounts claimed. [D] What the isotopes cannot do is identify a species; they report a category. A researcher who wants to know which root or which grain is still dependent on the fragile, unpredictable survival of the plant itself, and so the older bias has not so much been removed as pushed back a step.