Chennai sees drastic decline in saw-scaled viper population

In the 1980s, when herpetologist V Kalaiarasan was doing research in Chennai Snake Park, he had been able to find at least half a dozen saw-scaled vipers (Echis coloratus) under sicklebush trees in nearby Anna University.



“This venomous species was once commonly found in Chennai, Tiruvallur and Kancheepuram districts, though they are rarely found in these three districts now. The rapid urbanization and over-catching have pushed the species to the brink of extinction,” said herpetologist V Kalaiarasan. Care Earth Trust co-founder Ranjit Daniels said the reduction in the population of saw-scaled vipers did not happen recently. The state forest department in 2008-’09 asked the trust to assess the population of four venomous snakes after the Irulas wanted to catch more snakes.

“When I did the assessment in Chennai, Kancheepuram and Tiruvallur districts, the population of all the four species in the study area was less. Of the four, cobras are common. Saw-scaled vipers are rarely found. They are seen only in a few localities. The main reason is the loss of habitat. They prefer open grasslands, which have been taken for setting up industries,” he said.

Former conservator of forests S Paulraj said while the urbanization had eaten away the habitats of sawscaled vipers, the Irulas, who used to catch them for extracting venom, too, are responsible for the deterioration of their population.

"The trapped snakes are kept in pots for more than 20 days. This will hinder their normal movement. After extracting venom for four to six times, when these snakes are released in the wild, they will be sluggish," Paulraj said. "They will become easy prey for eagles, peafowl and other predatory birds," he added.

Former secretary and manager of Irula Society S Dravidamani said tribals were permitted by the forest department to catch snakes only from Chennai, Kancheepuram and Tiruvallur districts. With the decline in its population in these areas, they travel even further to Villupuram and Tiruvannamalai districts to get vipers.

Paulraj said the government should start similar societies across the state to avoid limiting catching of snakes to these three districts, thus providing employment opportunities for more people.

Denying the decrease in the viper population, Irula Society member Rajendran said they caught 2,800 sawscaled vipers last year in a two-week period.

“If their population in the wild dwindles, how can we get so many numbers within a short period?” he said.