Family : VIPERIDAE
Species : Trimeresurus sumatranus
Maximum Size : Females to 135 cm, males to ~90 cm

Trimeresurus sumatranus was first described in 1822 (as Coluber sumatranus) by Sir Stamford Raffles.

Vogel et al (2014) redefined the species in great detail; the reader should refer to their paper as the primary source of information for this species.

This impressive snake mainly inhabits rainforest, from the lowlands to lower montane elevations up to 1000 metres, as well as mangrove, swamps, and some plantations. It appears to be both diurnal and nocturnal, and is typically encountered in low vegetation. Its diet comprises small vertebrates including frogs, lizards and small mammals.

In the field this species may be distinguished from other pit vipers by it colouration and patterning. Its dorsum and flanks are green, and its ventral scales are yellow; these two colours are separated by a white or very pale yellow stripe on the lower flanks which runs the entire length of the body. The head is green above, yellow on the sides, and pale yellow beneath.

Most scales are edged with black, and adults have irregular black bars on each side of the body; dark bars may not be apparent in juveniles. The tail grades from green at the start to red at the tip. The eyes are dark grey.

Vogel et al (2014) summarize the range of this species as Sumatra (particularly the Barisan Mountains), much of Borneo, southern Thailand (Yala province) and Peninsular Malaysia (Perak, Terennganu, Pahang and Johor states).

The inclusion of Singapore in the range of this species appears unlikely, given the indeterminate status of historical records (see species checklist in Baker & Lim, 2012) and absence of any recent records.

Figs 1 and 2 : Juvenile or sub-adult example with an estimated total length of 50 cm, from streamside vegetation at Kubah, Sarawak, Borneo. This example has developed some faint dark barring on its flanks. Photos thanks to Law Ingg Thong


References :

Baker, N. & K. Lim, (Vertebrate Study Group, Nature Society Singapore), 2012 (Reprint). Wild Animals Of Singapore. Draco Publishing and Distribution Pte. Ltd.

Vogel, G., David, P. & Sidik, I. (2014). On Trimeresurus sumatranus (Raffles, 1822), with the designation of a neotype and the description of a new species of pitviper from Sumatra (Squamata: Viperidae: Crotalinae)