Adult Malayan Pit Viper in situ, found in a culvert in Krabi, Thailand.

[Page Updated: 4 April 2018]

Calloselasma rhodostoma (Malayan Pit Viper, Malaysian Pit Viper)

Thais say: Ngoo gap pa

Length: Usually less than 1 meter. Female Malayan Pit Vipers are the larger and fatter snakes. Males of the species don’t make it to 1 meter long.

Range: Thailand, Laos, Cambodia, Java, Sumatra, Malaysia, Vietnam, Burma, and China.

Notes: These vipers are similar to North American “copperhead” snakes. They prefer dry, flat areas. They are known as lazy snakes. They may not move out of the way at all if someone is walking right toward them. After they bite they are known to remain in the same location. There are thousands of bites per year in Malaysia and Thailand from this snake.

These snakes are so dangerous when handled because they are not consistent with their behavior. One day they will be calm. The next, or the next 10 minutes – they will violently strike out lightening fast. Their preferred habitat is under dry leaves, wood, or rocks. They are active during the night mostly, especially during rain.

Juvenile (neonate) Malayan Pit Viper with white-tipped tail. — A neonate Malayan Pit Viper showing the white-tipped tail it shakes to bring prey closer.

Nickname: Finger rotters – given by Al Coritz, Viperkeeper on YouTube. If they get you in the finger – you’ll likely lose part of your finger, hand, or arm without immediate care.

Habitat: Forests, rubber plantations, bamboo patches, farmland, grassland. Often lies in the short or long grass. These are terrestrial snakes that I’ve never seen climb anything.

Active Time? Day if cloudy and/or rainy, and night.

Food: Mice, frogs, lizards. Predominantly rodents.

Malayan Pit Viper from southern Thailand — *Calloselasma rhodostoma*. Malayan Pit Viper. Usually under a meter, and thick. Very common. Very dangerous.

Defensive Behavior: Partially coiled with neck in an “S”. Their strike is very fast. Their fangs are long – and in the front of the mouth. Some strikes are short, others involve the whole body as it “jumps” at the same time it strikes. Don’t underestimate the distance this snake can reach when striking. Also, this snake is VERY good at striking behind its head. Watch the video.

This pit viper has the longest fangs of any other snake in Thailand – including the Siamese Viper (D. siamensis).

Malayan Pit Viper (Calloselasma rhodostoma) skull showing fangs, jaws, and dentition. Skull is at Queen Saovabha Memorial Institute in Bangkok, Thailand.

Venom Toxicity: Very toxic. Venom is necrotoxic – it destroys all cells it comes in contact with – red blood cells, muscle, ligaments, and bone. With a quick hospital visit after a bite you may just lose part of your finger, or some tissue where the bite occurred. The venom causes a bite victim to bleed from body orifices – eyes, nose, mouth, ears, sexual organs, and sometimes fatally in the brain. Most people don’t die if they go to the hospital. Deaths occur when bite victims delay seeking medical treatment. There is antivenom for this snake.

If you are bitten by this snake, do NOT wrap a tight band around the bite location. That will stop the venom from moving, from being diluted, and the tissue will suffer much more destruction.

Offspring: Lay eggs. Female guards them. Young are about 9 inches long and fast and thin. They are fully able to bite, and have full strength venom.

Malayan Pit Viper Eating Mouse Video – close up of large fangs, strike, etc.

Malayan Pit Viper Scientific Classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Subfamily: Crotilinae
Genus: Calloselasma
Species: C. rhodostoma

Binomial Classification:
Calloselasma rhodostoma

Video – Malayan Pit Viper Color Variety in Thailand

Venomous Snakebites and Near Misses!

More than 34 stories of venomous snakebite and very near misses from Southeast Asia’s most deadly snakes – King Cobra, Malayan Pit Viper, Monocled Cobra, Banded Krait, Malayan Krait, and more! Digital Book with over 100 pages by Vern Lovic.