Family : VIPERIDAE
Species : Tropidolaemus wagleri
Maximum Size : Females 92 cm, males 52 cm

Wagler's Pit Viper, or Temple Pit Viper, is perhaps the commonest pit viper in Southeast Asia. It occurs in lowland forest, either primary or secondary, and in some coastal regions may occur in mangrove.

Pit vipers are all venomous, however Wagler's Pit Viper is generally not considered to be aggressive. In the field, these snakes are most easily identified by their markedly triangular head. 

Wagler's Pit Viper is generally found resting on low vegetation, but a careful search may also locate the species at mid-canopy level many metres above the ground.

Individuals may remain on the same branch for many days, either as they digest a recent meal, or as they lie in wait for their next meal. Prey is detected at night by means of the heat-sensing pits which occur on either side of the head.  Rodents, such as arboreal rats, and birds reportedly make up the bulk of their diet.

Juveniles and males have a slender, lime green dorsum sparsely patterned with pairs of small coloured spots or short bars either side of the vertebral line: these spots or bars are partly red and partly cream (longer bars indicate a juvenile female). There is a bicoloured stripe passing through the eye which comprises a thick red stripe below, and a thin white stripe above. The end of the tail is reddish brown.

In females the body is more thickset, dark above and pale yellow to white below. Numerous irregular pale yellow bands cross the body, and there is a thick dark stripe along the side of the head. The top of the head is mainly black.

This species occurs in southern Thailand, southern Vietnam, Peninsular Malaysia, Singapore and parts of Indonesia including Sumatra and adjacent smaller islands, and the Riau Archipelago.

The Bornean Keeled Pit Viper T. subannulatus, was once considered to be a form of Wagler's Pit Viper, but is now considered a separate species.

Figs 1 and 2 : Adult female in secondary forest at Seletar, Singapore.

Figs 3 and 4 : Mating pair in low vegetation at the edge of secondary forest, Singapore.

Fig 5 : Sub-adult female on a low branch of a fig tree, at the edge of Singapore's central forests.

Fig 6 : Juvenile, probably male, on low vegetation in secondary forest, Singapore.

Fig 7 : Head of a male in a fig tree at Bukit Timah, Singapore.

Fig 8 : Juvenile female, with long bicoloured bars, in Singapore's central forests.

Fig 9 : Example from Johor, Peninsular Malaysia with vibrant green body colour.


References :

Vogel, G., P. David, M. Lutz. van Rooijen & N. Vidal. 2007. Revision of the Tropidolaemus wagleri complex (Serpentes: Viperidae: Crotalinae). I. Definition of included taxa and redescription of Tropidolaemus wagleri (Boie, 1827). Zootaxa 1644: 1-40.