Wild animal injuries are distinct from other injuries sustained by humans; tearing, cutting, penetrating, and crushing injuries are sometimes combined with falls and large animal forces causing blunt trauma. Bites from attacking animals may cause local infection, and wounds are potentially contaminated with a variety of pathogens. In addition, animals can transmit systemic diseases, many of which induce substantial morbidity and mortality. To compound the problem, many animal attacks occur in remote or wilderness areas and involve substantial delays in the time to notification, rescue, and presentation to definitive care. This article discusses attacks by the most common North American wild mammals.