Shore pit viper

This is a stout snake with a broad, triangular head, a narrow neck and rough, strongly keeled scales. Like other pit vipers it has a heat-sensing pit between each eye and nostril, and vertical pupils.

Colour varies a lot. Many are plain dark grey or purplish-brown. Others are brown with a faint pattern, or greenish-yellow with dark mottling. Some have a pale stripe along the lower edge of each side.

Its scientific name, purpureomaculatus, means purple-spotted, although many individuals have no purple spots.

It is a specialist of mangroves and coastal forest. Singapore records include the mangroves of Sungei Buloh and Pasir Ris.

By day it usually rests 1 to 2 m off the ground on low branches, roots and tree trunks.

Beyond Singapore, it is found in Myanmar, southern Thailand, Peninsular Malaysia and Sumatra.

Little has been published on its diet. Pit vipers of its group take small animals such as lizards, frogs, birds and rodents. In Singapore it has been recorded climbing down from the trees onto the mud to catch and swallow a crab-eating water snake. Like other pit vipers, it uses its heat pits to sense warm-blooded prey in the dark.

During the day it stays coiled and still, relying on camouflage, and like most pit vipers it is thought to hunt mainly after dark. It is known for striking readily at a perceived threat, with little or no warning.

Its dull grey and purple-brown colours match mangrove bark and the mud below, so a resting snake is very hard to spot even at close range.

It has its own predators. In Singapore it has been recorded being eaten by king cobras, and records also mention estuarine crocodiles and buffy fish owls.

Females are larger than males, reaching about 90 cm compared with about 67 cm for males. The young develop in eggs kept inside the mother's body, and are born live, ready to fend for themselves.

Yes. Its venom mainly affects blood and tissue. Bites can cause marked pain and swelling, and some cases involve serious bleeding problems that need antivenom. In Malaysia it was the pit viper most often involved in confirmed bites referred to a national envenomation consultancy service from 2017 to 2020, with no deaths recorded in that study.