Behaviour 2019
Variation in cortisol metabolites in wild samango monkeys: Resources, risks, and human shields
Laura R LaBarge1, 2, Andrew TL Allan2, 3, Carol M Berman4, Russell A Hill2, 3, Susan W Margulis5. 1Program in Evolution, Ecology and Behavior, Dept. of Environment and Sustainability, The State University of New York, University at Buffalo, Buffalo, NY, United States; 2Primate and Predator Project, Makhado, Limpopo, South Africa; 3Dept. of Anthropology, Durham University, Durham, England, United Kingdom; 4Dept. of Anthropology, The State University of New York, University at Buffalo, Buffalo, NY, United States; 5Dept. of Animal Behavior, Ecology and Conservation, Canisius College, Buffalo, NY, United States

Animals that are habituated or tolerant to human presence may often benefit from “human shields” that provide a buffer against unhabituated predators or competitors. Yet, we currently know little about the physiological consequences of human shields. Here we investigated how the potentially conflicting effects of human presence, resource availability, climate, predation, and competition may be associated with variation in fecal cortisol metabolite levels (FCMs) in wild samango monkeys (Cercopithecus albogularis). We found evidence that FCMs tracked with water scarcity, food availability, and challenges to thermoregulation in this mountain-dwelling population. FCMs were also higher on the day following several predator encounters. Yet, as the number of human observers increased, FCM levels associated with predation events flattened. Thus, ecological challenges track with FCMs in this study population, but human presence may affect samangos’ perception of risk.