Assessing the reactive behavioural-physiological characteristics of captive Moschus chrysogaster: implications for ex-situ conservation and captive breeding

Translocation, captive breeding and reintroduction to the wild are often used for the conservation of endangered animals. However, in captivity, wild animals may develop behavioural and physiological traits akin to domestication, such as reduced reactivity (similar to being more tame), which could have negative impacts on their reintroduction into the wild. This study was conducted from January 2021 to December 2023 at the Zhuanglang Moschus chrysogaster (hereinafter – musk deer) Breeding Farm in Gansu Province (China). The study recorded the intensity of reactive behaviour of 26 male musk deer, specifically their avoidance reactions to keeper and aggressive behaviour towards conspecifics. Faecal samples were also collected during the same period for the detection of cortisol metabolites. Principal component analysis was used to explore the behavioural and physiological characteristics of captive-bred musk deer in terms of reactivity. Based on these characteristic indicators, cluster analysis was conducted to assess the degree of reactivity of individual musk deer, dividing the 26 animals into high-reactivity and low-reactivity groups (i.e. more-tame vs. less-tame individuals). Subsequently, the study investigated the relationships between reactivity degree and age, musk secretion volume. The results showed that musk deer with a lower degree of reactivity exhibited reduced fear of humans and weaker aggressive behaviour towards conspecifics. Among 26 musk deer, five individuals were classified as the low-reactivity group, while others were in the high-reactivity group. The degree of reactivity was negatively correlated with age. There was no significant difference in musk secretion volume between the high-reactivity and low-reactivity groups (though the high-reactivity group showed a slight, non-significant decrease). Based on this study, it is recommended that musk deer farms construct different breeding environments for musk deer according to the breeding purposes. For musk deer intended for reintroduction to the wild, it is suggested to maintain their solitary living conditions and minimise human contact to preserve their wild nature.