Since 2006, IERC has been studying the relationships between fishers and their main predators in California, bobcats, mountain lions, and coyotes. After concern by the Hoopa Fisher Project that their radio-collared fishers were experiencing an unexpectedly high rate of predation, IERC began investigating which predators were responsible for fisher predation, the physical characteristics of predation events, and predation patterns of individual predators. We do this by sampling predated fisher carcasses for predator DNA, amplifying the DNA so that we can identify species, and in most cases, identifying the individual predator responsible through the use of microsatellites. These techniques worked so well at identifying predators that we expanded them to assess predation of American martens, Vancouver Island marmots, black-tailed deer, and livestock.