Sumatran Pit Viper
Trimeresurus sumatranus • Order: Squamata, Suborder: Serpentes, Family: Viperidae, Subfamily: Crotalinae, Genus: Trimeresurus, Species: Trimeresurus sumatranus
Venomous Status
Highly venomous (Solenoglyphous; featuring long, hollow, retractable fangs located at the front of the upper jaw).
Danger Level
High Risk. Bites are medically significant and potentially life-threatening if untreated. While fatalities are rare due to the availability of antivenom and hospital care, the venom can cause localized tissue damage and systemic coagulopathy.
Geographic Range
Southeast Asia, specifically Indonesia (Sumatra, Mentawai, Nias, Bangka, Belitung Islands), Malaysia (Peninsular Malaysia and Sarawak/Sabah on Borneo), Thailand, and Singapore.
Conservation Status
Least Concern (IUCN). However, local populations face threats from rapid habitat loss due to deforestation for palm oil plantations and the exotic pet trade.
Physical Description
A vibrant green body often featuring reddish-brown or purplish crossbands. The head is large, distinct from the neck, and triangular. It has vertically elliptical pupils, heat-sensing pits between the eyes and nostrils, and heavily keeled scales. A white or pale postocular stripe is often present.
Size & Dimensions
The specimen in the image appears to be a subadult. Adults typically range from 80 to 110 cm (approx. 32 to 43 inches) in total length, though females can occasionally reach 130 cm.
Habitat
Found in lowland wet forests, hill forests, and occasionally mangrove swamps at elevations up to 800 meters. They occupy microhabitats such as tree branches, vines, and shrubs near streams.
Behavior & Temperament
Primarily nocturnal and arboreal. It is a sedentary ambush predator that remains motionless for long periods. While generally calm, it will strike quickly and repeatedly if agitated or threatened. It uses its prehensile tail to anchor to branches.
Diet & Feeding
Diet consists primarily of small rodents, birds, and lizards. It employs an ambush 'sit-and-wait' strategy, using its heat-sensing pits to detect warm-blooded prey, which it strikes and holds until the venom takes effect.
Reproduction
Viviparous (gives birth to live young). A typical litter consists of 10 to 20 neonates, which are born fully functional and venomous.
Venom Profile
Venom Type
Procoagulant and hemotoxic venom with mild cytotoxic effects. It causes local swelling, severe pain, tissue necrosis, and can disrupt blood clotting mechanisms.
AI-generated — see a qualified source if acting on this. For any snakebite, call emergency services immediately.
Look-alikes
Often confused with Tropidolaemus wagleri (Wagler's Pit Viper), which has different color phases and smoother scales, and Trimeresurus insularis (White-lipped Pit Viper), which lacks the reddish-brown crossbanding on the body.
Conservation Status
Least Concern (IUCN). However, local populations face threats from rapid habitat loss due to deforestation for palm oil plantations and the exotic pet trade.
Cultural Significance
Feared by local populations due to its camouflage and potential for accidental encounters. Ecologically, it serves as an apex predator in its microhabitat, controlling rodent and lizard populations.
Notable Features
Features a highly prehensile tail used for balance in the canopy and heat-sensing loreal pits that allow it to forage in complete darkness by detecting infrared radiation from prey.