Sri Lankan Green Pit Viper

The Sri Lankan green pit viper, known locally as pala polonga, is a venomous pit viper endemic to Sri Lanka. It is a mid-sized, cylindrical snake with a flattened, triangular head that is distinct from the neck and a pit on each side of the head between eye and nostril. Newborns measure 20 to 25 cm. Males reach 60 to 75 cm, while the considerably larger females can grow to 130 cm. The body is bulky and the short tail is prehensile, suiting a tree-dwelling life (Wikipedia, general species account).

Colour is variable and cryptic. It is typically green with a black variegated pattern and usually a black line behind the eye, and the tail is black. Wet zone snakes have the black markings more clearly defined, and males tend towards blue while females are mostly green. The species is viviparous, producing about 5 to 25 young at a time. Nationally Least Concern (Sri Lanka National Red List 2012, listed as Trimeresurus trigonocephalus).