2015 Elsevier Inc. All rights reserved. The study of laboratory animal behavior has increased steadily over the last decade, with expanding emphasis on a variety of commonly used species. In the United States, this trend was initially focused on species for which there was a regulatory requirement to consider normalizing behavior, specifically the U.S. Department of Agriculture's requirement to promote the psychological well-being of nonhuman primates as reflected in the 1991 Animal Welfare Regulations (AWRs). With the advent of the seventh edition of the Guide (NRC, 1996), more emphasis was placed on addressing the structural, social, and activity elements in all laboratory animals' cage or pen environments in what was referred to as a 'behavioral management program.' The implication that environmental enrichment is a de facto means of normalizing laboratory animal behavior is evidenced by the discussion of this topic as one component of the microenvironment (i.e., cage) for all laboratory species in the eighth edition of the Guide (NRC, 2011). The 2011 Guide also devoted an entire section to 'Behavioral and Social Management,' highlighting the importance of motor, cognitive, and social activity; the social environment, noting that single housing of social species should be the exception; and procedural habituation and training of animals.
