Extralimital urban movement of a Golden Langur Trachypithecus geei (Khajuria, 1956) in Nalbari District, Assam, India

The Golden Langur Trachypithecus geei is an endangered colobine primate endemic to a narrow transboundary belt of western Assam, India, and southern Bhutan, bounded by the Manas and Sankosh rivers and the Brahmaputra. Between 8 August 2025 and 18 January 2026, a solitary adult male was recorded during 12 observations across four locations-Dahudi, Tihu, Gamarimuri (Kaithalkuchi), and Nalbari Town-all urban and peri-urban settlements in Nalbari District that lie well outside the species’ known distribution, before reportedly continuing its movement further east. The animal used isolated Peepal Ficus religiosa trees, Atha Dimoru Ficus auriculata, Rain Tree Samanea saman, bamboo clumps, and other roadside and homestead vegetation as isolated patches while traversing the human-dominated matrix. We document these observations as an unusual extralimital excursion by a single dispersing individual, not as evidence of a new or expanding distribution range, and discuss probable causes, welfare risks (electrocution, vehicular traffic, and free-ranging dogs), and implications for conservation in human-dominated landscapes of the Brahmaputra floodplain.