title: Efficacy of 3 types of foraging enrichment for rhesus macaques (Macaca mulatta).
abstract: Primate facilities provide environmental enrichment to improve animal wellbeing, increase opportunities for expression of species-typical behaviors, and decrease the occurrence of stereotypic behaviors. The current study assessed the efficacy of 3 types of foraging enrichment: puzzle  balls, supertubes, and shakers. We assigned 48 rhesus macaques to 3 experimental groups, each of which received (after a 3-wk baseline observation period) 1 of the 3 enrichment devices intermittently for 3 wk. Observations were collected during 10-min sessions by using 1-0 sampling with  15-s intervals (480 h total). Observations were collected at the same 10 specified time points each week during the baseline period and after enrichment. Data were analyzed by using generalized linear mixed-effects modeling under the assumption that the underlying response followed a Poisson  distribution. Foraging behavior increased significantly in all 3 groups and remained increased in some groups when enrichment was removed after 43 h. The 3 enrichment devices had different effects on individual expression of stereotypy: supertubes decreased it, shakers increased it, and puzzle  balls led to a decrease followed by an increase. We present potential reasons for the changes in stereotypy and postulate a likely balance between the beneficial and negative effects of enrichment in any given environment.
authors.affiliation: California National Primate Research Center, Animal Behavior Graduate Group, School of Veterinary Medicine, University of California-Davis, CA, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Gottlieb
authors.forename: Stephanie
authors.initials: S
authors.lastname: Ghirardo
authors.forename: Darren E
authors.initials: DE
authors.lastname: Minier
authors.forename: Nicole
authors.initials: N
authors.lastname: Sharpe
authors.forename: Lindsay
authors.initials: L
authors.lastname: Tatum
authors.forename: Brenda
authors.initials: B
authors.lastname: McCowan
mesh_terms: D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006799:Housing, Animal / Q000592:standards*; D016014:Linear Models; D008253:Macaca mulatta / Q000502:physiology / Q000523:psychology*; D008297:Male; D013239:Stereotyped Behavior / Q000502:physiology*; D013997:Time Factors