The Psychological Well-Being of Nonhuman Primates (1998)

National Research Council

Abstract

Concise guidelines for the adequate housing and handling of captive nonhuman primates. We can expect institutions to monitor and assess the conditions of animals in their charge and to make appropriate efforts to improve conditions that do not meet the criteria of psychological well-being. These criteria are: Appropriate social companionship. Opportunities to engage in behavior related to foraging, exploration, and other activities appropriate to the species, age, sex, and condition of the animal. Housing that permits suitable postural and locomotor expression. Interactions with personnel that are generally positive and not a source of unnecessary stress. Procedures that reduce reliance on forced restraint ... are less stressful for animals and staff, safer for both, and generally more efficient [p. 45]. Wild marmosets and tamarins only occasionally descend to the ground and in captivity prefer to be above caregiving personnel. Therefore, it is advisable not to house these primates in two-tier cages [p. 70]. Social interactions are considered to be one of the most important factors influencing the psychological well-being of most nonhuman primates. ... Knowing that most primates benefit from social interactions, it should be obvious that they can be harmed by a lack of social interaction [p. 16]. ... The common practice of housing rhesus monkeys singly calls for special attention [p. 99] ... Every effort should be made to house these [singly caged] animals socially (in groups or pairs), but when this is not possible, the need for single housing should be documented by investigators and approved by the IACUC. ... Although the causes of self-directed biting are poorly understood, prolonged individual housing is probably an influential contributing factor. [p. 34] ... To reduce the stress of physical restraint, many primates can be trained for routine procedures. ... Under natural conditions, many primates spend much of their lives aboveground and escape upward to avoid terrestrial threats. Therefore, these animals might perceive the presence of humans above them as particularly threatening [p. 118]. ... Even macaques, which some describe as semiterrestrial, spend most of the day in elevated locations and seek the refuge of trees at night [p. 92]. ...Optimal use of available cage space might well depend more on the placement of perches, platforms, moving and stationary supports, and refuges than on cage size itself [p.118]. ... The animal technician's and caregiver's roles are pivotal to the social support of primates, particularly animals that are singly caged [p. 121. Enrichment methods that have not been subjected to empirical testing should be viewed simply as invalidated ideas, regardless of how well intended they might be. Without appropriate measurement and verification, we might do more harm than good in our efforts to improve animal conditions [p. 114].