Family: Viperidae (Vipers)
Subfamily: Crotalinae (Pit Vipers)

Picture: J. Bulian

Calloselasma rhodostoma (Malayan Pit Viper)
Thai: (ngu gap pha)

Length: Up to 100 cm

Occurrence: Resident in the whole of Thailand and is often found under dry leaves, stones or old wood.

Behaviour:
Predominantly nocturnal especially when it is drizzling, but also active during the day. It bites, is an aggressive snake and advances very quickly.

Picture: J. Bulian

Cryptelytrops [Trimeresurus] albolabris (Yellow-lipped Green Pit Viper)
Thai: (ngu khiau hang mei tong loeng)

Length: 75 cm - male, 104 cm - female

Occurrence: Throughout Thailand

Behaviour/habitat:
The White-lipped Pit Viper is a very adaptable snake and is at home in trees and in open land. It is often found near human settlements. It likes to be near to the water. The snake is nocturnal and searches for food on the ground at night. The Pit Viper bites quickly and such cases are frequent.

Note:
A normal person cannot tell the difference between the green Pit Vipers. The following Pit Vipers, present in Thailand, have a green colour:

• Cryptelytrops (Trimeresurus) albolabris (White-lipped Pit Viper)
• Viridovipera (Trimeresurus) gumprechti (Gumprecht's Pit Viper)
• Parias (Trimeresurus) hageni Hagen's Pit Viper
• Cryptelytrops (Trimeresurus) macrops (Large-eyed Pit Viper)
• Popeia (Trimeresurus) popeiorum popeiorum (Popes Pit Viper)
• Popeia (Trimeresurus) fucatus *in the works from MALHOTRA & THORPE (2004) not yet entered
• MALHOTRA & THORPE follows, entered here under the name Popeia
• Parias (Trimeresurus) sumatranus (Sumatra Pit Viper)
• Viridovipera (Trimeresurus) vogeli (Bird Pit Viper)

There is a serum against all green Pit Vipers available in Thailand.

Cryptelytrops [Trimeresurus] kanburiensis (Kanburi Pit Viper)
Thai:

Length: 70 cm

Occurrence: Area of Kanchanaburi

Behaviour:
Predominantly nocturnal and lives in bushes as well as in high grass. During the day, the snake can be found in fruit plantations.

Picture: J. Bulian

Cryptelytrops [Trimeresurus] macrops (Large-eyed Green Pit Viper)
Thai: (ngu kieo hang mi ta to)

Length: up to 72 cm
However these snakes usually only reach a length of around 50 cm.

Occurrence:
Northern and central Thailand. These little poisonous snakes are often found in the area around Bangkok.

Habitat and behaviour:
This is, just like other species of Trimeresurus, a snake which is active at night. When twilight falls, these snakes leave their daytime hideouts in bushes and trees where they sleep curled up in a ball, and go on the hunt in shrubs and on the ground for frogs, lizards, birds and rodents. Trimeresurus macrops is easily recognisable from other species of Trimeresurus due to its large yellow eyes. Although these animals usually sit on branches and ignore passers-by, they can bite as fast as lightning.

Danger:
Just like other species of Trimeresurus. The poison may be a little stronger than that of Trimeresurus albolbris. A poisonous bite does not generally lead to major complications.

Picture: J. Bulian

Cryptelytrops [Trimeresurus] venustus (Brown-spotted Green Pit Viper)
Thai:

Length: Max. 70 cm, but usually smaller

Occurrence: Between Chumphon and Krabi

Behaviour/habitat:
The Coloured Pit Viper prefers life in the woods and on limestone mountains but can also be found on rubber plantations. The snake is mainly nocturnal. The snakes are active during the day only after heavy rainfall. The snake lives almost only on the ground where it hunts frogs and lizards. The snake is very peaceful and only bites if seriously aggravated.

Danger:
Scientific studies on the strength of the poison have not yet been carried out. Reports from bite victims lead us to believe that the poison is not as strong as the White-lipped Pit Viper. Victims have reported pains but no long-lasting effects.

Picture: J. Bulian

Popeia [Trimeresurus] popeiorum (Pope's Pitviper)
Thai: (ngu kieo hang mi tong kieo)

Length: Up to 90 cm

Occurrence: To be found in central and west Thailand in the rain forest.

Behaviour:
A nocturnal, aggressive and biting snake which advances very quickly over a distance. During the day it lies around in the trees. At night it is on the move on the ground.

Picture: J. Bulian

[Trimeresurus] Cryptelytrops purpureomaculatus (Mangrove Pit Viper)
Thai: (ngu pang ka)

Length: 100 cm

Habitat: To be found on covered river banks, in sumps and in hilly areas.

Behaviour: An easily excitable, aggressive snake, which advances very quickly over a distance.

Picture: J. Bulian

Tropidolaemus wagleri (Wagler's Pitviper)
Thai: (ngu kieo tuk gae)

Length: Max. 100 cm. The male remains smaller than the female.

Occurrence: In southern Thailand from the Khao Sok National Park and Takua Pha up to the Malayan border.

Behaviour/habitat:
The Wagler’s Pit Viper is nocturnal snake and a resident of the lowlands. It lives in primary and secondary forests and in mangrove forests. In these forests, it is mostly found in bushes and on branches at a height of 2 meters. These snakes do not move very much and sometimes spend weeks in the same spot without moving. In general, the animal does not bite quickly but can strike out extremely quickly.