McCully, C. L., MacAllister, R. P., Smedley, J. et al. 2014. The longevity of a nonhuman primate social housing strategy: A review of group housing for rhesus male macaques maintained on active protocols in biomedical research. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 566-567 (Abstract #PS67).

Regulatory mandates promoting the psychologic wellbeing and addressing the social needs of nonhuman primates have been well described. In response to these directives, in 1992, we initially reported a successful group housing strategy for instrumented rhesus macaques accessed routinely for biomedical research. Small groups of macaques were successfully established and maintained. These groups consisted predominately of males with subcutaneous CNS catheters and intravenous ports, which were removed from their groups for 0.5 to 20 d with successful return. This social housing strategy did not impede any research requirements or results, and has been effectively and continuously used for 22 y within our facility. A review of the social housing history from 2003 to 2014 was done for 28 male macaques ranging in age from 2 to 20 y. The type of instrumentation implanted; psychologic status; and the number, success, duration, removal and returns to groups for each animal were recorded and analyzed. Eighty-two percent of the macaques were instrumented with subcutaneous CNS catheters, cannulas, or lumbar and intravenous ports. Each macaque, on average, was involved in 2.4 groupings; 30% were involved in 3 to 6 groupings. On average the grouping success rate was 65% and 5.4 m in duration. The longest group duration was 61 m. There were 113 removals from groups with a 92.8% successful return rate. All grouped macaques were accessed, on average, at a frequency of once/animal/month with successfully removal/returns for 92.9% after 1 to 4 h, 35.7% for 2 to 7 and 17.9% for 14 to 35 d of absence from group. Grouping and return failures were attributed to aggression. The longevity and effective use of this social housing strategy has been successfully demonstrated. Instrumented male rhesus macaques can be socially housed and maintained on active research protocols.