The transition from Middle to Upper Paleolithic is a major biological and cultural threshold in the construction of our common humanity. Technological and behavioral changes happened simultaneously to a major climatic cooling, which reached its acme with the Heinrich 4 event, forcing the human populations to develop new strategies for the exploitation of their environment. The recent fieldwork at Les Cottés (France) transitional site offers a good opportunity to document subsistence strategies for this period and to provide for the first time high-resolution insights on its evolution. We present the results of the complete zooarchaeological and taphonomic analysis of the transitional sequence, associated with a large regional synthesis of the subsistence strategy evolution during the Middle to Upper Paleolithic. We conclude that, while there is no major change in the hunting strategies, the butchery activities evolved in strict correlation with the development of range weapons. In addition, the demise of carnivore seems to be a consequence of the human pressure on the environment. Our study demonstrates how the faunal component of the environment became a structuring element of the human social organization, being at the base of future cultural evolutions.