This article investigates the environment of the laboratory animal as a site where animal welfare and behavioral neuroscience intersect, creating opportunities for cross-pollinations between the concepts and practices of each field. Laboratory animal welfare is organized around a distinction between the care of animals and their use in experiments, and while best practices for animal handling and the management of animal housing may appear to fall firmly within the ambit of animal care, behavioral researchers' own histories of work on 'experimenter effects' and 'enriched environments' complicate this distinction. Using historical and ethnographic data from animal behavioral neuroscience laboratories, this article examines how welfare professionals have drawn on behavioral science as a source of new data and techniques, and how researchers in turn employ concepts from animal welfare in their scientific thinking. This investigation provides insight into how changes in animal welfare oversight are changing scientific practice, but it also reveals one reason why taking seriously the idea of the animal as a situated, interactive being in laboratory practice remains difficult. Professional conflicts over the management of the animal's environment and rhetorical troubles created by the association of gene-environment interaction research with welfare agendas complicate both the management and meaning of interaction in the animal behavioral neuroscience laboratory.