RESUMEN
BACKGROUND: The behavior of animals is modified by captivity. Environmental enrichment (EE) is a program designed to enhance the welfare of confined animals by providing them with a more stimulating background. This is carried out by the implementation of a series of activities that encourages them to present behaviors typical of their species, as well as keeps them active. The aim of this study was the evaluation of the influence of the EE in the behavioral variables in a colony of 24 stumptail macaques (Macaca arctoides). Our hypothesis is that the application of this program will reduce aggression, stereotypes and coprophilia behaviors and, at the same time, will increase exploration and solitary play. METHODS: The behavioral frequency previous to EE was compared with that during EE implementation. RESULTS: Our results showed that aggression, coprophilia stereotypic behaviors and social play were significantly reduced during EE, whereas exploration was significantly enhanced. The response of the individuals according to gender was similar for both sexes. CONCLUSIONS: Environmental enrichment programs are indispensable for captive animals' wellbeing as they reduce aggression and stress while providing animals both physical and cognitive entertainment.