Maracas for Macaca? Evaluation of three potential enrichment objects in two species of zoo-housed macaques

Abstract

One group each of Barbary macaques and stumptailed macaques, both zoo-housed, received hard replica fruits in three experimental conditions: as empty (“unresponsive”) objects, as maracas which rattled when manipulated (“simple responsive”), and as objects from which food items could be extracted (“foraging devices”). Both groups manipulated the replica fruits most when they functioned as foraging devices, and responsiveness tended to decrease within sessions in all conditions. Thus, objects which increase the animals’ sense of control in addition to providing food rewards appeared particularly suitable as enrichment devices, although novelty and indirect behavioral effects point to the need for thorough evaluation of enrichment interventions.