Short-term effects of an environmental enrichment program for adult cynomolgus monkeys

Behavior patterns (including behavior disorders) of cynomolgus monkeys are established early in life, and exploratory behavior lessens with age. Whether environmental enrichment programs benefit these animals can be questioned, particularly for animals housed short-term. We evaluated the overall effect of our environmental enrichment program in 40 newly arrived male and female adult cynomolgus monkeys to determine whether it impacted animal well-being. Animals allocated into two groups one that received environmental enrichment (the enriched group) and one that did not (the nonenriched, control group) and behaviors were assessed over a 5-week period. We also examined the effect of enrichment on training time for a simple activity (entering a transfer box). Animals that had environmental enrichment made use of additional cage space, toys, and foraging items, but trends in observed in-cage behavior patterns were relatively unchanged throughout the course of the study. After study completion, physical evidence of self-trauma was found in 25% of the nonenriched animals but not in any of those in the enriched group. Enrichment had no notable effect on body weight or training time for a simple activity. Our findings suggest that provision of a comprehensive environmental enrichment program provides a beneficial effect to adult cynomolgus macaques singly housed short-term.