Gottlieb, D. H., Tatum, L., Ghirardo, S. et al. 2009. Assessment of efficacy of three types of foraging enrichment in rhesus macaques (Macaca mulatta). American Journal of Primatology 71(S1), 33. (32nd Meeting of the American Society of Primatologists Scientific Program, Abstract #13)

Rhesus macaques housed indoors in captivity commonly display abnormal behaviors that are rarely seen in their wild counterparts. These behaviors include stereotypic behaviors and self-abuse. These behaviors are often seen as signs of poor welfare, due to stressors in the environment or a lack of stimulation. As a result, environmental enrichment is commonly used in captive primate facilities to improve welfare. The objective of this study was to assess the efficacy of three types of foraging devices. Thirty-six monkeys from CNPRC were assigned to three experimental groups, each of which received, after 3-week baseline observations, one of the three enrichment devices intermittently for three weeks. Observations were conducted for 10-minute sessions using one-zero sampling on 15- second intervals [360 hours total]. Observations were collected at the same 10 specified time points a week during baseline and post-enrichment receipt. Motor stereotypies were recorded during baseline in all three experimental groups, and self-abuse was recorded in two groups. Data were analyzed using negative binomial regression. We found a significant decrease in motor stereotypies in all three groups [p < 0.01], but enrichment devices differed as to the timing of that decrease. A significant decrease in self-abusive behavior was found during the first hour of puzzle ball enrichment [p < 0.01], while a nonsignificant decrease was found with “supertube” enrichment. These results show that foraging enrichment has mitigating effects on some behavioral problems.