Wagler's Pit Viper

 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. 

The Wagler's pit viper is a carnivore. That means that they eat other animals. They hunt at night. The adult feeds on lizards, birds, and rodents. Snakes in the tropics don't need to use food energy to keep themselves warm. Snakes can also get all the energy they need with just 3 meals a month.

• Venom

The venom of Wagler's Pit Viper is haemotoxic. While the bite is not regarded as fatal, it may cause severe pain and local swelling. A unique family of peptides called "Waglerins" (Schmidt et al., 1992) was isolated from Wagler's Pit Viper venom. Unlike other peptides which have proteolytic and haemolytic activity, these family of Waglerin peptides apparent lack of neurotoxicity imply that the venom has a unique mechanism of action. One of the compounds in its venom, Waglerin-1, has been found to have the novel function of blocking nicotinic acetylcholine receptors at the neuromuscular junction, blocking uptake of Na+ and thus inhibiting muscular movements (McArdle et al., 1999).

The heat-sensing pits that so give pit-vipers their name convergently evolved in Viperidae as well as in the more primitive Boidae and Pythonidae. In Viperidae, the pits have evolved only once while the labial pits seen today in Boidae and Pythonidae have evolved multiple times. While the electrophysiology of the pits appear similar, the pits of the two lineages differ in gross structural anatomy.

These pits enable the animals to have what we would imagine to be infrared vision of heat wavelengths between 5 - 30 nanometers. Despite the fact of the long-standing belief that these pits evolved to function in detecting prey, recent studies suggest thermoregulation and predator detection may have also contributed to the evolution of this complex sensory organ.

• Stark Sexual Dimorphism

                         A male rests on top of a female Wagler's pit viper

Here are differences between male Wagler's Pit Viper and female Wagler's Pit Viper.

 

Adult females: 

1. body black with yellow crossbands
2. black postocular stripe
3. banded belly
4. 23-27 dorsal scale rows at midbody, distinctly keeled
5. 134-147 ventral scales
6. 45-54 subcaudal scales
7. maximum length of up 100 cm

Adult males: 

1. body vividly green and white spots
2. white & red postocular stripe
3. uniform belly
4. 23 dorsal scale rows at midbody, feebly keeled
5. 143-152 ventral scales
6. 50-55 subcaudal scales
7. maximum length of 75 cm