Long-Term Trends, Seasonality, and Spatial Patterns of Human Casualties from Sloth Bear Attacks in Chitwan National Park, Nepal

The sloth bear (Melursus ursinus) is both ecologically important and among the most feared wildlife species in southern Nepal. Despite this, long-term patterns of human–sloth bear conflict have not been well documented. This study assessed the annual, seasonal, and spatial patterns of human casualties resulting from sloth bear encounters in Chitwan National Park, Nepal. Verified incident records from 1999 to 2025, along with household surveys of 100 households, were used to describe trends and patterns in human-sloth bear interactions. Over 27 years, 196 human casualties were recorded, including one fatality. Annual casualties ranged from 1 to 29 and demonstrated a significant downward trend according to the Mann–Kendall test. Negative binomial regression, accounting for over dispersion, estimated an annual decline of 4.47% (p = 0.0012). Casualties were unevenly distributed seasonally, with winter (36%) and spring (32%) accounting for most casualties. Spatially, conflicts were recorded in 15 of 22 buffer zone user committees, with more than half occurring in the southwestern sector, particularly in the Madi Valley. Household surveys indicated that most encounters involved forest- and agriculture-dependent communities and frequently occurred while people were walking or undertaking forest activities. Most human sloth bear conflict incidents involved single bears, although mother–cub groups accounted for 31% of encounters. Despite the declining long-term trend, conflict remains spatially and seasonally concentrated. These findings provide a baseline for targeted conflict prevention, community safety measures, and long-term sloth bear conservation in Nepal.