Abstract: Social rank of animals has important effects on individuals’ resource allocation, community stability and individuals’ behavioral strategies. Steroid hormone level of captive animals is correlated with feeding and management, which can reflect the extent of animals’ social stress. Understanding the relationships between social rank and steroid hormone level in captive forest musk deer is the precondition and basis of successful ex situ onservation and breeding of musk deer. From June 15^th to August 15^th, 2018, 25 forest musk deer (Moschus berezovskii) were sampled and the social rank was calculated by using focus sampling and special event recording methods. The fecal steroid hormone concentration was measured by radioimmunoassay method. The relationships between the social rank of forest musk deer and the concentration of cortisol, testosterone and estradiol in fecal samples were analyzed. The results showed that the estradiol concentration of low rank captive female forest musk deer (289.037±59.710 pg·g^-1, n=11) was significantly higher than that of high rank ones (45.670±27.283 pg·g^-1,n=6) (P<0.05), and the testosterone concentration of low social rank males (3.863±1.538 ng·g^-1, n=3) was not different from that of high rank ones (8.017±1.295 ng·g^-1, n=5) (P>0.05). No significant differences were found in cortisol concentration between low-rank (37.891±7.564 ng·g^-1, n=3) and high-rank males (29.947±2.441 ng·g^-1,n=5), and between low-rank (37.262±1.544 ng·g^-1, n=11) and high rank females (37.478±4.628 ng·g^-1,n=6) (P>0.05). Regardless of sex, the cortisol concentration of low-rank forest musk deer (37.397±1.826 ng·g^-1,n=14) was not different from that of high-rank ones (34.055±2.886 ng·g^-1,n=11) (P>0.05). The social rank of female captive musk deer negatively correlated with fecal estradiol level, while the level of estradiol in low-rank females was significantly higher than that in high-rank ones. Social rank and the changes of fecal estradiol level of the musk deer can be monitored to predict the behavioral health and reproductive performance in the farming practices.

Key words: forest musk deer (Moschus berezovskii), captivity, social rank, cortisol, testosterone, estradiol.