Hervé Bocherens - Neanderthal palaeoecology: Insights from stable isotopes

Описание: Hervé Bocherens - Neanderthal palaeoecology: Insights from stable isotopes

Part of #NEANDERTHAL: The Conference which was organised by the Gibraltar National Museum from 13th to 15th September 2018 at the University of Gibraltar.

Since almost three decades, carbon and nitrogen isotopic composition of fossil bone collagen has been used to reconstruct the diet of Neanderthals. Based on the fact that “you are what you eat”, at least in terms of isotopic composition of your body tissues, and since different food resources have different isotopic signatures, it is possible to quantify the consumption of specific food resources by ancient hominins, provided that some collagen is still preserved in their bones. The comparison of the isotopic composition of bone collagen in Neanderthals, in their potential prey and in coeval predators allows us to determine where the Neanderthals fit in a given trophic system, i.e. which prey they consumed the most and with which predators they were in competition.

So far about 30 Neanderthals specimens were analyzed with this approach, but not all comply with the reliability criteria. Moreover, analyzing cut-marked bones from Middle Palaeolithic sites also provide valuable information on the habitat of the prey consumed by Neanderthals. Comparing isotopic results from sites from different climatic contexts provides information about the ecological flexibility of Neanderthals. In temperate contexts, it is possible to test to which extent were the Neanderthals able to exploit forested environments. However, bone collagen reflects essentially the protein part of the diet, so it biased towards protein-rich food resources, such as meat and fish, and tends to underestimate plant foods.
Fortunately, additional approaches are available to evaluate the whole diet in complement to the protein part of the diet, such as carbonate isotopic analysis and the newly developed isotopic analysis of single amino acids from bone collagen. Carbonate in tooth enamel has a better potential for long-term preservation than collagen, especially in warm contexts. Single amino acid isotopic analysis is able to reconstruct the trophic position of an omnivore, i.e. the relative proportion of plant and animal food consumed, as well as helping deciphering the possible contribution of aquatic resources in ancient hominin diet. Finally, new Bayesian model approaches yield more statistical results about proportions of food resources. All these methodological developments open new possibilities for a more accurate diet reconstruction of Neanderthals and to understand better their position in their respective ecosystem.

© Gibraltar National Museum, 2018