Hanging in the balance: an ecological and conservation assessment reveals growing threats to the Bamboo Pitviper, Trimeresurus (Craspedocephalus) gramineus (Shaw, 1802), in the Dangs Forest of Gujarat, India

Abstract The Bamboo Pitviper, Trimeresurus ( Craspedocephalus ) gramineus , is the only pitviper species in Gujarat, India, where it reaches the northern limit of its range. It is recognized as a species of Least Concern based on IUCN Red List criteria, but critical aspects of its ecology, behaviour, and conservation status remain understudied. We conducted intermittent road-based visual encounter surveys along two forest roads in Gujarat’s Dangs District from January 2022–May 2025 and recorded 44 individual snakes. Pitvipers were predominantly observed at heights of 3–7 m on vegetation jutting out from cliff-like cut slopes, including exposed roots (56%), low shrubs and bushes (30%), and bamboo (14%). Six experimentally displaced individuals exhibited site fidelity and returned to their original perches within 72 h. Snakes were seen exclusively at night (19:00–03:00 h), and encounter frequency was markedly reduced during monsoons. Behavioural observations revealed cryptic positioning in the vegetation, ambush hunting near retreat sites in the soil, slow movement, and defensive displays (fang extension and tail vibration). The repeated presence of pairs suggests seasonal monogamy during courtship until the female starts to produce offspring, and the breeding period appears to coincide with the time of highest detectability. Habitat fragmentation and illegal wildlife trade emerged as important threats, and we document one trafficking incident. Our findings underscore the need for targeted conservation efforts and identify T. gramineus as a potential model species for studying arboreal pitviper ecology. To this end, we propose designating no-cut zones to mitigate erosion and protect pitviper habitat so that continuous monitoring is possible.