Radio collars, meant for tracking the behaviour of tigers in the Sunderbans as part of the ongoing census, will be custom-made. For, the big cats here “are nearly half the size” of their terrestrial counterparts.
Authorities of the Sunderbans Reserve will observe the two tigers that have been radio-collared before any new collar is put around the neck of the animals, Field Director Subrat Mukherjee told The Hindu on Thursday.
Along with the nationwide estimation exercise, the Sunderbans has been identified for a Rs. 35-lakh project to radio-collar 6-8 tigers and compare the behaviour of the big cats living on the estuarine islands with that of the animals living elsewhere in the country.
But the project experienced hiccups after some radio collars slipped off the tigers. Experts from the Wildlife Institute of India, led by Dr. Y. Jhalla, came to the Reserve two months ago to look into the matter. “We found that the tigers in Sunderbans are much smaller in terms of body mass than tigers in the rest of the country, which is probably why the collars slipped off,” Dr. Jhalla said.
Subsequently, collars were shortened, but from now on only custom-made collars would be put on the tigers, he said.
The experts team fixed two collars, both of which have been transmitting signals regularly for the past month, including signals from a tigress that ventured across the border into Bangladesh.
An average big cat weighs about 250 kg, whereas Sunderban tigers weigh about 100 kg. Their girth at the neck is also significantly small – about 45 cm compared to 75 cm of tigers elsewhere, according to Dr. Jhalla.
Pradeep Vyas, Director, Sunderban Biosphere Reserve, said the probable reason for their leaner build and smaller body mass was the difficulty of the terrain they live in. The Sunderbans is the only mangrove region in the world known to be inhabited by tigers.
The Sunderban tiger has to swim long distances and negotiate marshy areas and spiky pneumatophores. Its prey base is also leaner, comprising spotted deer, wild boar and monitor lizards. Tigers elsewhere may be preying on larger animals, he says.