1 Introduction Norway rat [Rattus norvegicus (Berkenhout, 1769)] and black rat [Rattus rattus (Linnaeus, 1758)] infestations are common in cities around the world, and these infestations are associated with a variety of economic, social, and public health harms. Over the past 15 years of research on rats, the Vancouver Rat Project (VRP) has demonstrated that these harms occur at the unique interfaces among rats, people, pathogens, and the environment.