Some anthropologists have argued that communal hunts played an important role in the evolution of hominids. Variation in the frequency and timing of bison hunts on the Great Plains has been explained with the Annual, Vore, and Fat Depletion Models. According to the Annual Model, hunts were organized in the fall to obtain stores of meat for consumption during the winter. The Vore Model refines the Annual Model by proposing that larger and more frequent bison kills occurred during periods with higher precipitation, better grazing conditions, and greater numbers of bison. Different animals may be more intensively butchered and processed to obtain meat from fatter bison, even when many animals were malnourished. Expectations of the Vore and Annual Models are not supported by the analysis of dates, bison remains (dental wear and pathologies, post-cranial cortical thickness), and paleoclimatic indicators recovered from kill-sites throughout the Plains. The proportion and numbers of kill-sites are too low to represent annual events. Almost as many kills occurred in the spring and the fall. Many hunts were accomplished when the bison were in poor health and under diverse grazing and environmental conditions. Instead of being a response to subsistence and environmental problems, many communal hunts served to mediate social and political tensions by providing food and exchangeable items for human aggregations. Feasting, ceremonies, and exchanges could instill a sense of solidarity among participants and contribute to the mediation of tensions created by differences in power, wealth, gender, and age.
