Fifth of the world's reptiles threatened by extinction: study

Indian crocodile, king cobra among species in great danger of disappearing forever

By Soma Basu
Published: Saturday 16 February 2013

Indian crocodile or mugger (Courtesy Adam Jones, PhD Global Photo Archive)

An estimated 19 per cent of the world’s reptiles, including the Indian crocodile (mugger) and king cobra, are threatened with extinction, states a paper published on February 16 by the Zoological Society of London (ZSL) in collaboration with experts from the IUCN Species Survival Commission (SSC).

The study, published in the journal Biological Conservation, is the first of its kind, summarising the global conservation status of reptiles. More than 200 world-renowned experts assessed the extinction risk of 1,500 randomly selected reptiles from across the globe. There are known to be approximately 10,000 species of reptile on Earth, first appearing around 300 million years ago.

Of the estimated 19 per cent of reptiles threatened with extinction, 12 per cent have been classified as critically endangered, 41 per cent endangered and 47 per cent vulnerable, the journal reports.

The Indian crocodile, king cobra, the South Andaman krait, four types of turtles—Bengal roof turtle, red-crowned roofed turtle, hawksbill turtle and jagged shelled turtle—along with the Sikkimese bent-toed gecko have been identified to be in great danger of disappearing forever. There is no available information on the conservation status of nearly one in three reptiles in India.

Three critically endangered species were also highlighted as possibly extinct. One of these, a jungle runner lizard, Ameiva vittata, has only ever been recorded in one part of Bolivia, according to a ZSL statement.

Levels of threat remain particularly high in tropical regions, mainly as a result of habitat conversion for agriculture and logging. With the lizard's habitat virtually destroyed, two recent searches for the species have been unsuccessful.

Extinction risk is not evenly spread throughout this highly diverse group: freshwater turtles are at particularly high risk, mirroring greater levels of threat in freshwater biodiversity around the world. Overall, the study estimated 30 per cent of freshwater reptiles to be close to extinction, a percentage which rises to 50 per cent when considering freshwater turtles alone, as they are also affected by national and international trade.

Monika Bohm, from ZSL, who led the study, said: "Reptiles are often associated with extreme habitats and tough environmental conditions, so it is easy to assume that they will be fine in our changing world."

"However, many species are very highly specialised in terms of habitat use and the climatic conditions they require for day-to-day functioning. This makes them particularly sensitive to environmental changes. We found that a large number of reptiles in India have been listed as data deficient (27 per cent). These are species that have to be targeted for further research," Bohm added.

Collectively referred to as reptiles, snakes, lizards, amphisbaenia (also known as worm lizards), crocodiles, and tuataras have had a long and complex evolutionary history, having first appeared on the planet around 300 million years ago.

Head of ZSL's Indicators and Assessment Unit, Ben Collen said: "These findings provide a shortcut to allow important conservation decisions to be made as soon as possible and firmly place reptiles on the conservation map."


The conservation status of the world’s reptiles 

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