The Comparative Effect of Occupational and Musical Enrichment on Fecal Glucocorticoid Metabolite Levels in a Captive Colony of Stumptail Macaques (Macaca arctoides)

• Published in: Biology (Basel, Switzerland) Vol. 13; no. 2; p. 124
• Main Authors: Mayagoitia-Novales, Lilian, Cerda-Molina, Ana Lilia, Martín-Guerrero, María Andrea, Muñoz-Zamudio, Emmanuel, Estudillo-Mendoza, Gema R., Borráz-León, Javier I.
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.02.2024
• Subjects: adults; Age; Aggression; Animal behavior; Animal welfare; Animals; Behavior; Biological Sciences; Captivity; Corticosteroids; Dominance hierarchies; Enrichment; enrichment programs; environmental enrichment; equations; fecal glucocorticoid metabolites; Feces; Females; Glucocorticoids; Juveniles; Macaca arctoides; Males; Metabolites; Music; music enrichment; Music therapy; occupational enrichment; Physiological aspects; Physiology; primate welfare; Primates; Sex differences; Social aspects; Social behavior; Social rank; social structure; Stereotyped behavior; Stress (Psychology); Stress response; Visual stimuli; Zoo animals; Zoos; Mexico; United States > US; primate welfare; music enrichment; Macaca arctoides; fecal glucocorticoid metabolites; occupational enrichment; enrichment programs
• ISSN: 2079-7737; 2079-7737
• DOI: 10.3390/biology13020124

Environmental enrichment improves captive animal welfare by reducing stress-related behaviors. Previous studies in a captive colony of stumptail macaques (Macaca arctoides) reported a reduction of aggression, coprophilia, and stereotypic behaviors after an occupational enrichment program; however, the effect on stress hormones such as glucocorticoids has not been investigated yet. The goal of this study was to compare the effect of sex, age, and social rank on changes in fecal glucocorticoid metabolites (fGCM) after applying two kinds of enrichments (occupational vs. musical) in a captive colony of stumptail macaques. We collected 234 fecal samples from 25 stumptail macaques under the following conditions: (1) basal (no enrichment), (2) three weeks of occupational enrichment, and (3) three weeks of relaxing/classical music. The Generalized Estimated Equation Model showed an increase in fGCM levels after the occupational enrichment only in adult subjects (p = 0.003 compared to basal). The fGCM levels reached by the adults after the occupational enrichment was higher than that of juveniles (p = 0.002) and subadults (p = 0.02). Occupational and musical enrichment decreased fGCM levels only in middle-ranking individuals (p < 0.001 and p = 0.013, respectively). No sex differences were found. In conclusion, there were age and rank differences in individuals’ physiological reactivity to the effects of environmental enrichment which need to be considered when planning enrichment programs.