Trimeresurus sumatranus
Silhouette: Steven Traver · PhyloPic
In 3 days ~40% in a week ~70%
Trimeresurus sumatranus is a species of venomous pitviper (a subfamily of vipers within the larger Viperidae family) found in the tropical forests of Indonesia, Malaysia and Thailand. Arboreal by nature, its coloration is pale to neon-green, with some black vertical markings, and a red-tipped tail. As with other vipers, this species has prominent, "keeled" scales, which appear somewhat raised and give the snake a rough-textured appearance. Common names include Sumatran pitviper, Sumatran tree viper, and Sumatran pit viper.
Trimeresurus sumatranus is a large heavy-bodied pitviper, with a prehensile tail. Adults may attain 1.6 metres (5 feet 3 inches) SVL (snout–vent length), with fangs over 10 mm (3⁄8 in) long. It is an arboreal species that is pale green in color with a red tail. The dorsal scales are edged with black, which may form crossbands in more mature specimens. There is a white or yellow stripe on each side along the first row of dorsal scales. Ventrally it is greenish or yellowish, and the ventral scales may be thinly edged with black.
Scalation includes 21 (23) rows of dorsal scales at midbody, 183–190/182–191 ventral scales in males/females, 57–66/55–64... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Kinabalu Park | 🇲🇾 Malaysia | |
| 2 | Danum Valley Conservation Area | 🇲🇾 Malaysia |
Possible
About 20% of wildlife watchers report a Sumatra Pit Viper sighting in Danum Valley Conservation Area on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 24th most-seen of the 35 reptiles we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
September
In that month about 40% of wildlife watchers report a Sumatra Pit Viper in Danum Valley Conservation Area on a given day, against under 5% in November to July, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Sumatra Pit Viper sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Sumatra Pit Viper sightings, Danum Valley Conservation Area ranks 2nd at about 20%. The best odds are in Kinabalu Park (Malaysia, about 30%).
GBIF citizen-science records
It is estimated from how often the Sumatra Pit Viper is recorded against all the reptiles logged in Danum Valley Conservation Area (7 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
