Saturday, November 28, 2009

poisonous snakes in Sri Lanka

There are about 93 species of land and and sea snakes in SriLanka. But only 5 of the land snakes are considered potentially deadly. It is estimated that there are about 65,000 snake bites resulting in over 800 deaths annually in SriLanka. Nevertheless, snakes are an ecologically important group of animals in our ecosystems, adding to the biodiversity of the country. Their venoms are valuable natural substances in research.

Common Cobra (Naja naja naja)

Sinhala: Naya, Nagaya
Tamil: Naga pambu, Nalla pambu

The naya possesses an expansible hood carrying a spectacles-shaped marking on its upper surface, and the third upper lip-scale, and touches the nasal-scale and the eye. They are highly venomous. They have cylindrical bodies with long tails and smooth scales.

Common krait (Bungarus caeruleus)

Sinhala: Thel karawala, Maga mruwa
Tamil: Yennai panayan,Yennai Viriyan, Yettadi viriyan

Common krait is mainly confined to the dry zone plains up to about 300 m. The karawala is identified by the enlarged row of scales along the top of its back, and by the third upper lip-scale touching the nasal-scale and the eye. It is black in colour with a series of white rings that disappear with age. They are highly venomous.

Ceylon Krait (Bungarus ceylonicus)

Sinhala: Dunu Karawala, Polon Karawala
Tamil: Yennai panayan,Yennai Viriyan, Yettadi viriyan

Ceylon or Sri Lanka krait inhabits the wet and intermediate climatic zones from 30 m up to 2000 m above the mean sea level.

The brown, grey, black, brick red and white coloration of the Russell's viper (Daboia russelii) and Echis carinatus helps them to merge well with the soil, dry vegetation, rocks and logs where the two species rest during the day. Similarly, the green, yellow and black colour of the Green pit viper (Trimeresurus trigonocephalus) merges into the foliage of the trees, shrubs and creepers on which they rest, resulting in a fair number of people being bitten by green pit vipers while plucking tea leaves, clearing forests and weeding.

Russell’s viper (Daboia russelli russelli)

Sinhala: Thith Polanga, Dara polanga
Tamil: kanardi viriyan

The head of the tit-polonga is wider than the neck and its top is covered with small scales, the nostril is large, and a large scale exists over each eye. Along the back is a row of 22 to 24 elliptical markings up to above the base of the tail, and a row of fig-shaped lateral blotches. It is highly venomous.

Saw- Scaled Viper (Echis carinatus)

Sinhala: Vali Polanga
Tamil: Surattai pambu, Pal surattai

Mapila (Cat-snake)

Sinhala: Mapila

Mapilas are tree-dwelling snakes of which four species are found in Sri Lanka. Some are light-brown, others are dark-brown or light-red, and they either possess dark cross bars or blotches, or lack such markings. They are venomous.

The majority of the deaths are caused by the common cobra, common Karit and the Russell’s Viper. Some of the moderately or mildly venomous snakes found in SriLanka are as follows. These snakes causes only local envenoming.

The brown, grey and black cryptic coloration of Hypnale camouflages it well amongst dry fallen leaves and other vegetation on the ground. Its resting coiled posture of its body and holding its head elevated at an angle of 45, resembles a dry curled leaf (mainly rubber, coffee or cashew (Anacardum occidentale L.) plantations where Hypnale hypnale is common.

Merrem’s hump nosed Viper (Hypnale hypnale)

Sinhala: Polon thelissa, Kunakatuwa

The kunakatuwa has the front half of the top of the head covered with large scales and possesses a pit between the nostril and the eye, a small bump exists at the tip of its snout. Its markings are irregular blotches either on a brown, pink, grey or yellow background. It is venomous but rarely fatal.

Sri Lanka hump- nosed viper (Hypnale nepa)

Sinhala: Mukalan kunakatuwa

Green pit Viper(Trimeresurus trigonocephalus)
Sinhala: Pala Polanga
Tamil: Pachai viriyan, Kopi viriyan

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