The national park east and west ranges in the tiger reserve area and the Raidighi range in the South 24-Parganas forest division, with good number of crocodile sightings, show that these areas have so far been able to withstand climate change elements like salinity and surface water temperature. Otherwise, experts said, these places couldn't have sustained a healthy crocodile population.

"The national park east range with 40 direct and 51 indirect sightings have turned out to support the best population of the giant reptiles, followed by Sajnekhali range with 30 direct and 14 indirect sightings. National park west range followed with sightings of 28 direct and 15 indirect evidences of crocodiles. Ramganga range recorded 15 direct and 3 indirect evidences of crocodiles and also supported the best juvenile population," said Wildlife Institute of India (WII) scientist BC Chowdhury.

According to Pradeep Vyas, director of Sunderbans Biosphere Reserve (SBR), a good sub-adult or juvenile population in Ramganga range proves that this area has the potential to sustain a healthy number of crocodiles in future.

"The crocodile population in these areas also shows that the salinity level here is moderate, making it perfect for the survival of these reptiles. The surface water temperature, too, seems to be conducive to a healthy crocodile population here. As the apex predators of water don't have sex chromosome, the temperature plays a key role in determining the sex of the crocodile hatchlings," added Vyas. On salinity, Vyas said the reptiles can sustain a salinity up to 20 ppt (parts per thousands).

Shailendra Singh of Madras Crocodile Bank Trust said the unique eco-system of Sunderbans is ideal for crocodile survival. Suchandra Kundu of Society for Heritage and Ecological Research (SHER), which had participated in the census in January, said apart from the crocodile status, such exercise also helps understand the water quality and prey base in the mangroves.