Abstract

Species’ activity patterns are driven by the need to meet basic requirements such as food, social interactions, movement, and rest. A variety of biotic and abiotic factors often influence these behaviors. From 2011 to 2021 we used camera-trap data to describe and compare the seasonal and daily activity patterns of the relatively poorly studied Asiatic black bear (Ursus thibetanus) across 2 study areas on the western and eastern macro slopes of the Sikhote-Alin Ridge (Russia) with differing climate characteristics. We analyzed data from 2,396 independent photo-records, including 225 near denning trees during hibernation. We used a Relative Abundant Index (RAI) for seasonal activity analysis and kernel density estimator based on the time of independent photographic events to calculate the proportion of diurnal, crepuscular, and nocturnal activity of each study area and period. Bears were active on average from 2 April to 3 November on the western macro slope and from 24 March to 8 November on the eastern one, which amounted to 59% and 63% of the year, respectively. Males stayed in dens for 5 months, whereas females with cubs used denning sites for up to 6.5 months. Winter activity was observed on the milder eastern slope (RAI = 0.09) during nut- and acorn-abundant seasons. The mean RAI during the active period for all sexes and ages (Apr–Oct) was 2.6, peaking in September (RAI = 4.8) and August (RAI = 4.3), correlating with feeding and fruit ripening. We compared daily activity patterns for different types of camera-trap locations and found that there were no significant differences (activity overlap coefficient Δ₄ varied from 0.81 to 0.93). Daily activity varied across calendar seasons, peaking from 07:00 hours to 19:00 hours. Diurnal activity was predominant (79.73%), with notable crepuscular activity in autumn (19.96%) and winter (21.74%). Nocturnal activity did not differ significantly between seasons. Significant overlap in daily activity was observed between warm and cold seasons (Δ₄ = 0.78). The indicators we obtained can be used as a basis for further monitoring the well-being of the Asiatic black bear population at the northern border of the range.

Sergey A. Kolchin, Aleksey Yu. Oleynikov, Evgeniia V. Volkova, and Galina P. Salkina “Activity patterns of the Asiatic black bear in the Russian Far East based on camera-trap data,” Ursus 2025(36e6), 1-16, (27 May 2025). https://doi.org/10.2192/URSUS-D-23-00024R1