Stable-Carbon Isotope Ratios as a Measure of Marine Versus Terrestrial Protein in Ancient Diets

Abstract
The stable-carbon isotope ratios for the flesh of marine and terrestrial animals from Canada's Pacific coast differ by 7.9 ± 0.4 per mil, reflecting the7 per mil difference between oceanic and atmospheric carbon. This difference is passed on to human consumers. The carbon isotopic values (δ13C) for human collagen thus yield direct information on the relative amounts of marine and terrestrial foods in prehistoric diets.