Abstract:

Aims: The black musk deer (Moschus fuscus) is listed as an endangered (EN) species on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species and is classified as a first-class National Key Protected Wildlife in China. However, prior research has predominantly focused on its taxonomy, morphology, and localized distribution surveys. Meanwhile, understanding the distribution and activity rhythms of sympatric ungulates can help elucidate their niche relationships and coexistence mechanisms. 

Methods: Data were collected from 169 infrared cameras deployed in Gedang, Medog, Southeastern Xizang from April 2023 to June 2025, which systematically monitored the black musk deer and its sympatric ungulate species. 

Results: The results revealed that among the six ungulate species, there were a total of 3,255 independent detections, with the black musk deer detected 202 times, indicating a relatively low relative abundance index (RAI = 3.38). The black musk deer was primarily detected at high elevations > 3,500 m, accounting for 70.30 % of its total solitary independent detections. In contrast, other ungulate species exhibited lower elevation preferences. Himalayan serow (Capricornis thar) and Himalayan takin (Budorcas taxicolor) exhibited wide elevational ranges across high- and low-elevation habitats, whereas red goral (Naemorhedus baileyi), Gongshan muntjac (Muntiacus gongshanensis) and wild boar (Sus scrofa) preferred mid- to low-elevation habitats. The distribution pattern of these species reflects a “vertical stratification” mechanism of habitat-niche partitioning. Seasonal activity patterns revealed that the black musk deer had a higher activity frequency in winter, peaking in January. Meanwhile, the species displayed the lowest lower critical ambient temperature threshold for activity among sympatric ungulates across spring, autumn and winter, and its upper and mean ambient temperatures during activity in all seasons were also the lowest recorded among these species, underscoring its adaptation to alpine-cold environments. Additionally, the black musk deer exhibited a significant nocturnal characteristic, with a night-time relative abundance index (NRAI) as high as 0.98. Daily activity rhythm analysis revealed that the black musk deer began to be active at 17:00 in the evening, with activity frequency increasing until it peaked at 3:00 in the early morning; during the daytime from 10:00 to 16:00, there were virtually no records of black musk deer activity. There was a significant differentiation in the daily activity rhythms between the black musk deer and its sympatric ungulate species, especially with the diurnal wild boar, with an activity overlap index of only 0.14. 

Conclusion: Based on extensive field surveys, this study provided the first detailed insights into the “high elevation + extremely nocturnal” pattern of habitat selection and activity rhythms of the black musk deer population, offering important scientific basis for the conservation and management of the wild population of this species and rare and endangered wild animals in Southeastern Xizang, as well as subsequent research.

Key words: Moschus fuscus, ungulates, Southeastern Xizang, activity rhythm, infrared camera, wildlife monitoring