Wednesday, November 13, 2013

Vine Snakes of Sri Lanka

Vine snakes belonging to the colubridae family with few number of species. In Sri Lanka there are two vine snake species have been identified by herpetologists till now. Vine snakes are well known among the people due to the mythical believes.

1) Green Vine Snake


Green vine snake is a slender arboreal snake belonging to the genus "Ahaetulla". Its scientific name is "Ahaetulla Nasuta" which is the same name sri lankans used to call it. Sri Lankans call it "ඇහැටුල්ලා" (Ahaetulla) or "ඇස්ගුල්ලා" (As gulla) which means the eye plucker, people believe this snake attack to the eye and pluck it off, makes no sense..all these are mythological believes. Since it's an arboreal snake and likes to hang on small tree branches and vines, most of the time people get bitten in face areas. maybe that helped to pop up such a myth among people. The coloration of the snake helps it to blend well with the habitat of the snake. This camouflage is hard to spot and humans are aware of it and gets bitten.

Green vine snake is distributed through out the island except high hill areas. It's a common snake in the land up to 1000m from sea level. Dorsal coloration is mostly bright green although there are nasutas with brownish color (Not Pulverulenta). Green vine snake can grow up to around 150cm in length. At birth baby vine snakes measures around 30cm. There is a small tip at end of the long snout which is easy to identify. Head is covered with elaborately shaped scales. Unlike other common snakes Ahaetulla species have horizontal pupils in their convex eye. The eye sight of Ahaetulla is sensitive to even small movements. Having a sharp eyesight is a characteristic of all arboreal snakes.

Vine snakes have Opisthoglyph fangs, in other words rear fangs. check the image above, you can see the fangs of Nasuta in the upper jaw. Ahaetulla Nasuta is a mildly venomous snake. Local swelling and itchiness in bite area can be seen as bite symptoms but it will reduce after 3-4 days. It's always better to get medical treatment for a bite of this snake since harmful bacteria could contain in it's fangs. It's a diurnal arboreal snake. These snakes mainly feed on agamid lizards, geckos and small warm blooded animals. According to Anslem De Silva, the pioneer herpetologist in Sri Lanka, Ahautulla also feeds on amphibian egg sacks on trees.

When threatened it puff up it's body to appear big as much as it can and shows a threat display by opening the mouth at the direction of threat. This puff up scene makes the black and white scales on body visible even better. Mating takes in June of each year. After a 6 months of gestation period,  female Ahaetulla nasuta gives live birth to around 5-15 offspring.

                                                 Ahaetulla nasuta giving birth to live offspring

Here is a small video about Green vine snake in sinhala language.

Small English review

Be careful when handling the vine snake as it's known for not liked to be handled. when it cannot adapt to the body temperature of the handler, this snake easily tempt to attack.

2) Brown Speckled Whip Snake / Brown Vine Snake

Brown vine snake carries the same characteristics of green vine snake, not much data is collected about this snake. In Sri Lanka it's called as "හෙනකඳයා " (Henakandaya) which means thunderbolt snake or Snake with a massive body. I have no idea why it's called like that. Maybe it strike with a lightning speed. Since it's a slender snake like a yard bean no point of calling as a snake with a massive body/trunk. The main difference of Brown vine snake over the green species Ahatuella Nasuta is Pulverulenta species have even longer snout and a pointed tip at end of snout. Dorsal coloration is light brown with dark brown speckled on scales.

This snake can be found in low and middle country belonging to intermediate, wet and dry zones in the island. most common around kandy district.

Just like the green vine snake, Brown vine snake also grow up to around 150cm and prey on small lizards and small mammals, some times small birds also in the diet. Opisthoglyph fangs are located and mildly venomous to humans.

Ahaetulla Pulverulenta is a ovoviviparous snake and gives birth to live offspring. 6-12 young are produced at a single gestation period.

This is the most interesting part, Henakandaya or A.pulverulenta is the root cause of the name "Anaconda". even Wikipedia says so. Click Here to See The Post about Anaconda's Name Origin in Wikipedia . Still cant believe? here's the story. As i said, ancient Sri Lankan people had lot mythological bevies about snakes. They haven't encountered with this snake often so they believed if the shadow of Henakandaya drops over a human being , he/she will get a muscle ache in back. therefore people went to the forest with fear of this snakes shadow. Once the Portuguese invade Sri Lanka they heard the rumors about a giant snake named henakandaya living in jungles of Sri Lanka. Portuguese had a hard time of pronouncing Sinhalese words. They call this snake as "Enakanda" As we all know Portuguese invaded the Brazil where the Amazon forest is located. They found a giant snake in the amazon forest and thought this could be the same snake that lives deep within Sri Lankan woods and started to call it as Enakanda. Later this word became "Anaconda"

Both Ahaetulla species in Sri Lanka is in danger. People often kill these snakes due to mythological believes. Snakes are part of the nature and a link in the food chain. by killing them we make the food chain unstable. So please be concerned not to harm this beautiful slender snake next time when you find a live specimen.

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