Approximately 50-100 million vertebrate animals1 are used, worldwide, in biomedical and behavioral experiments each year (House of Lords 2002; Taylor et al. 2008). The research occurs in universities, hospitals, laboratories, government facilities, and corporations. Animals are used to study disease and injury and to assess the risks posed by drugs, chemicals, pesticides, cosmetics, and the like. Some of the research produces useful generalizable knowledge for the treatment of human disease, injury, and discomfort, but much of it fails to yield medical applications and presents moral problems about scientific uses of animals.