What Drives Mortality in Tufted Grey Langurs (Semnopithecus priam priam) Across Habitats and Seasons in the Western Ghats?

Abstract

The tufted grey langur (Semnopithecus priam priam), a folivorous primate endemic to South India, plays a pivotal role in forest regeneration through seed dispersal. However, anthropogenic pressures—including electrocution, road kills, and habitat fragmentation—pose significant threats to its survival. This study investigates habitat-specific and seasonal mortality patterns of the tufted grey langur in and around the Kalakad-Mundanthurai Tiger Reserve (KMTR), Tamil Nadu. Data were collected through opportunistic observations and community interviews from December 2017 to February 2022. Mortality events were classified by cause—electrocution, road kill, fighting, predation, and infanticide—and analyzed across three habitat types (village, foothills, and forest) and three seasons (dry, southwest monsoon, northeast monsoon). Statistical analyses revealed significant associations between mortality type and habitat (χ² = 18.45, p < 0.01), with electrocution incidents peaking in villages during the northeast monsoon and road kills occurring predominantly in forest habitats across all seasons. Fighting and predation were primarily recorded in forested regions, especially during the dry and northeast monsoon periods. Seasonal variations were significant (F(2,24) = 4.78, p < 0.05), indicating the influence of ecological and anthropogenic factors on mortality rates. These findings underscore the urgent need for seasonally and spatially targeted conservation strategies such as insulating electrical lines in villages and implementing wildlife crossings in forested areas to reduce mortality and ensure the long-term viability of this ecologically important species.