Conservation scientists increasingly recognize the need to incorporate the social sciences into policy decisions. In practice, however, considerable challenges to integrating the social and natural sciences remain. In this article, we review the US Fish and Wildlife Service's (FWS) 2009 decision to remove the northern Rocky Mountain population of gray wolves from the federal list of endangered species. We examine the FWS's arguments concerning the threat posed by humans' attitudes toward wolves in light of the existing social science literature. Our analysis found support for only one of four arguments underlying the FWS's assessment of public attitudes as a potential threat to wolves. Although we found an extensive literature on attitudes toward wolves, the FWS cited just one empirical research article. We conclude that when listing decisions rest on assumptions about society, these assumptions should be evaluated using the best available natural and social science research.