The question of when the Diné (or Navajo) became a distinct ethnic group has been the focus of research for over a century. Recent archaeological work in the Dinetah region of the American Southwest suggests that the Gobernador phase of Diné prehistory –roughly dated from A.D. 1650 to 1780– was a critical period for Diné ethnogenesis. Archaeological faunas from the Fruitland Data Recovery Project have been used to support this argument; these faunas seem to indicate a shift in subsistence from diets focused on small prey to those focused on larger animals between the Dinétah (A.D. 1500–1650) and Gobernador phases. A reanalysis of the Fruitland Project faunas, involving both refitting of bone and attention to taphonomic issues, does show an increase in representation of large prey during the Gobernador phase; however, this trend does not seem to be related to improved hunting efficiency or encounter rates. Rather, the increase may reflect changes in Diné subsistence and mobility in response to climate change.