Psychological Well-being and Environmental Enrichment of Nonhuman Primates

Providing for the psychological as well as the physical well-being of nonhuman primates maintained in captivity is a high priority. Psychological well-being is enhanced by appropriate social companionship (ie, compatible conspecifics); opportunities to engage in behavior related to foraging, exploration, and other activities appropriate to the species, age, gender, and physical condition of the animal; and housing that allows typical movement and resting postures. When home cages are of the minimum legal size, enlargements or added exercise areas should be encouraged. Interactions with human caretakers should be generally positive and not a source of undue stress. Well-designed and implemented environmental enrichment programs should meet these basic requirements, with the objective of minimizing traumatic injuries due to aggressive interactions, reducing the incidence of stereotypic and self-injurious behaviors, and ameliorating preexisting abnormal behaviors. Results of attempts to manage self-injurious behavior (eg, self-biting, hair plucking) with drugs such as benzodiazepines or haloperidol have been inconsistent, and longterm management is generally unrewarding. Socialization, which may involve visual and auditory stimuli as well as physical contact, appears to provide substantial benefit to most species of nonhuman primates, and should be provided within the constraints of research protocols and daily management practices. Additional enrichment options include forage boards or other food-related enrichment devices, manipulation mirrors, and a variety of cage toys provided on a rotating schedule to maintain novelty. Animal behavioral assessments as well as periodic review and evaluation of the effectiveness of enrichment program components should be performed by appropriately trained individuals.