Human diet evolution in Patagonia was driven by the expansion of Lama guanicoe after megafaunal extinctions

The interaction between human populations and their prey is of great interest in ecological, anthropological and archaeological studies. In Patagonia, several works have revealed the importance of one particular species in the diet of prehistoric human populations, the guanaco (Lama guanicoe). Especially after the megafaunal extinctions and, specifically, after 8000 years ago, the great predominance of guanaco in the diet of the hunter-gatherer groups from Patagonia has been pointed out. Here, we use zooarchaeological and molecular data to study the relationship between the changes in human diet in Patagonia during the Late Pleistocene-Holocene and the evolutionary and demographic history of guanaco populations. The joint use of these evidences allows us to quantitatively explore and discuss the changes in the human diet in an ecological context. The obtained results suggest an increase in the consumption of guanaco by the humans associated with a geographic and demographic expansion of this camelid in Patagonia after 10,000 years ago. These changes in the guanaco populations and human diet are also correlated with the previously described demographic changes of hunter-gatherer groups from Patagonia, suggesting a strong relationship among these phenomena.