Maned wolves (Chrysocyon brachyurus) differ in their responses to environmental enrichment: Why?

The maned wolf, a species vulnerable to extinction, is widely found in zoos. Environmental enrichment techniques have been recommended to increase environmental unpredictability, therefore stimulating behavioral diversity, and promoting welfare for zoo animals. However, diverse responses to unpredictability have been recorded in maned wolves, including increases in stress hormones, for unknown reasons. We aimed in this study to identify possible factors associated with the responses of maned wolves to enrichment. We tested the influence of temperament, sex, origin, rearing, and age on behavioral and hormonal responses of 13 captive maned wolves to feeding enrichment. Hormonal (fecal glucocorticoid metabolites – GCM - evaluation) and behavioral (by focal sampling and interval recording methods) data were gathered. We ran eight 5-minute sessions per animal per day, in three different stages: Baseline I, Enrichment, and Baseline II, 10-day long each. Temperament tests were also applied. Temperament, Sex, Environmental Enrichment, Age, and Origin were all factors influencing the behaviors of the maned wolves. Cautious females exhibited a tendency for greater locomotor activity than exploratory females, while GCM of both remained stable throughout experiment. The males had a reduction in GCM levels during the Environmental Enrichment stage and exhibited greater frequencies of Rest and Affiliative behavior than females. Younger animals exhibited higher frequencies of Locomotion, Foraging, and Affiliative behavior, and wild-born animals foraged more than captive-born wolves. As a whole, environmental enrichment had a potentially beneficial impact on the behaviors of males and females, resulting in a reduction of the time they were inactive and hiding. Our findings highlight the relevance of considering the specific needs of each sex and individual when planning environmental enrichment interventions for maned wolves. Such a procedure has the potential to improve the welfare of the individuals, by promoting environmental complexity and reducing stress responses, thus contributing to the ex-situ conservation of the species.