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.