Exceptionally high δ ¹⁵ N values in collagen single amino acids confirm Neandertals as high-trophic level carnivores

Significance Identifying past hominin diets is a key to understanding adaptation and biological evolution. Bone collagen isotope studies have added much to the discussion of Neandertal subsistence strategies, providing direct measures of diet. Neandertals consistently show very elevated nitrogen isotope values. These values have been seen as the signature of a top-level carnivore diet, but this interpretation was recently challenged by a number of additional theories. We here apply compound-specific isotope analysis of carbon and nitrogen in bone collagen single amino acids of two Neandertals. These Neandertals had the highest nitrogen isotope ratios of bulk collagen measured so far, and our study confirms that these values can be most parsimoniously explained by a carnivorous diet.