Trimeresurus

Trimeresurus is a genus of venomous snakes in the family Viperidae, subfamily Crotalinae, native to Asia. The group is commonly referred to as Asian green pit vipers, though coloration and patterning vary among species, and the taxonomy has been revised repeatedly. Many species previously placed in Trimeresurus have been reassigned to other genera, such as Cryptelytrops, Tropidolaemus, Popeia, and Viridovipera, leaving a core of species that remain in Trimeresurus in some classifications. This taxonomic complexity means the composition of the genus can differ among sources.

Most Trimeresurus species are slender, arboreal snakes that inhabit forests, shrublands, and sometimes grassy edges. They are typically green or green-tinged, often with stripes or crossbands, and they possess characteristic heat-sensing pit organs between the eyes and nostrils. Dorsal scales are usually keeled. These snakes are generally diurnal or crepuscular ambush predators that prey on lizards, frogs, birds, and small mammals.

Reproduction varies by species. Some Trimeresurus snakes are oviparous (egg-laying), while others are viviparous or ovoviviparous, depending on the lineage. Venom is used for prey capture and defense, and bites can be medically significant to humans in areas where they occur.

Geographically, Trimeresurus snakes range from the Himalayan foothills and southern China through Southeast Asia to the Indonesian archipelago and the Philippines. The conservation status of species within the genus varies widely, with habitat loss and collection for the pet trade posing threats to several species.