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A pit viper in your garden

May 19, 2012

Snakes are a reality to a monsoon gardener, even in towns and behind walls in gated communities. Although most Thai garden snakes are small and harmless to people, in fact beneficial by controlling rodents, treesparrows and snails, some snakes are potentially dangerous.

In a previous blog I treated the Indochinese spitting cobra. Yesterday Khun Nived picked up an upside down bucket on a stool and noticed a strange ‘stone’. When she looked closer she realized it was a snake. I was asked to come and take a look, and sure enough this was my first encounter with the pale form of the Malayan pit viper (Calloselasma rhodostoma, Viperidae, Crotalinae).

The snake was absolutely motionless, which is good and bad. It is good because it is not actively aggressive. It is bad because it trusts its camouflage so much that it will not move away like most other snakes, so if you put a hand or foot on it, it may bite. Luckily here in Chiang Mai there are good hospitals so the effects are usually not severe for an adult human, but without treatment you may lose a limb or even your life. I know of a gardener north of town who was bitten by this snake. He went to hospital but was back again at work the following day.

The pit viper venom contains compounds which lower the blood pressure (ACE inhibitors). This mechanism has been copied by modern science to make medicines against high blood pressure. Cilazapril is one such commercial medicine often used in Thailand against high blood pressure.

This relative of the rattlesnakes is nocturnal and hunts rodents but also other reptiles and amphibians. To be an efficient night hunter of rodents, it has a pit between the eye and the nostril which is sensitive to infra red, i.e. it can ‘see’ heat at night.

The Malayan pit viper is usually motionless if discovered.

If you are bitten by a snake, it is good to know which species to get accurate and swift treatment at the hospital. The body of the pale Malayan pit viper has distinct dark triangles. The body is thick, compared to that of the marbled cat snake. Another harmless look-alike is the banded kukri snake, but that species lacks the IR pit and has a round pupil.

Being a foreigner in a Thai garden I have to accept the Thai culture. This snake was killed by Khun Densak for safety reasons, but I took the opportunity to study it more closely. The pupil of the eye is just a slit. The pit for infra red vision is clearly seen between the eye and the nose pit. The elegant ‘eyebrow’ is another diagnostic feature.

To keep snakes away from areas where you live, it is good to keep some chicken. They hunt young snakes. A sighting of a venomous snake should encourage the house owner to keep children and pets indoors until next day. To my experience tropical snakes come and go, they rarely stay in one area for long. Most snakebite patients are men bitten in their hands when trying to kill a snake. At Dokmai Garden there are snake-hunting mongoose, guinea fowl and raptors and so we have only seen the Malayan pit viper once in five years. Nobody has ever been bitten by any snake at Dokmai Garden. Remember that Nived must have been very close to this snake when she picked up the bucket – still nothing happened. I am more worried about traffic accidents.

Text & Photo: Eric Danell

6 Comments leave one →
  1. May 19, 2012 3:22 AM

    Interesting snake. We here in the Top End of Australia also live with a variety of snakes. We are lucky, we can call out a free Government paid snake remover. I find the cactus in your first picture also very interesting. It has many interesting compounds too.

    • May 19, 2012 8:15 AM

      Yes, such a governmental system will probably come here too. We can get help to remove a python from the emergency squad, because pythons demand skill and many people.

      This special cactus is sold at the Khamtieng flower market. It demands shade and drought so I keep it under a roof. I need to make a well drained sand box to display cacti, but right now I focus on Asian plants. An orchid swamp has higher priority.


  2. May 19, 2012 9:50 AM

    I really must object to you saying: “Being a foreigner in a Thai garden I have to accept the Thai culture.”
    Culture or one might better say habits of any society normally has some bad old habits, like where I lived as a boy and everybody burnt leaves, or elsewhere where doors are not held open for others. Well leaf burning is a thing of a past in Melbourne and the air is cleaner for it. The society learnt and has become better. The culture has changed.

    Never-the-less it may well have been safer to kill the viper than to try to locate it. Would be nice to see safety become a part of the Thai culture.

    • May 19, 2012 2:56 PM

      One always has to make priorities, changing obsolete routines over night is impossible. Otherwise we would argue about every single thing, from child care to mowing. In this case the snake could have been moved to a nearby national park, but with unprofessional handling that would have been dangerous.

  3. juley permalink
    May 30, 2012 11:13 PM

    Where did you find it and please becareful naka
    Take care for all family ka


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