Behavioral and physiological responses of forest musk deer (Moschus berezovskii) to experimental fawn manipulation

摘要

High stress response is an important factor impeding the breeding of wild animals in captivity. Experimental fawn manipulation is considered a suitable approach to reduce the negative effects of behavioral and physiological stress. The forest musk deer (Moschus berezovskii) is classified as "endangered" by the IUCN Red List due to over-exploitation for musk production. Musk is highly valued for its cosmetic and alleged pharmaceutical properties and has stimulated the enthusiasm of captive musk deer breeding in recent years. This study attempts to reduce behavioral and physiological stress responses in juvenile musk deer using experimental fawn manipulation. Habituation started 5 days after birth and lasted until weaning age (90 days). We determined the behavioral stress response at the age of 30, 60, 90, 150, and 360 days by measuring acceptance or rejection of three treatment intensities (i.e., stroking, embracement) and quantified behavioral responses (urination, approaching the investigator). At the same time, physiological stress parameters were established, measuring the fecal glucocorticosteroid metabolite (FGM) concentration. Our results indicate that fawn manipulation initially reduced the behavioral stress, but after termination of treatments, stress symptoms reoccurred. We detected no difference in the FGM concentrations between treatment and control groups, suggesting that the experimental fawn manipulation did not decrease the physiological stress response. This implies that behavioral stress reduction cannot be sustained if the physiological stress remains unaltered. We argue that the socio-positive reactions of musk deer fawns to humans could be phenotypic and that the physiological stress response rather reflects their intrinsic characteristics than a successful manipulation.