Stretching from the mouth of the Hooghly River to the Bangladeshi border, the Sundarbans is the world’s largest mangrove forest – a vast labyrinth of tidal waterways, mudflats and forested islands formed by silt swept down from the Himalayas. Millions of people live in this ecologically fragile region on the Ganges Delta, but it also holds over 250 tigers. The big cats have developed unique strategies to cope with the distinctive habitat, among them extraordinary swimming skills that enable them to cross rivers in search of prey and mates.

The park was created in the 1970s to protect the local big cat population, but it also supports thriving numbers of saltwater crocs, Olive Ridley turtles, Gangetic dolphins and huge horseshoe crabs. Trips into the reserve are mostly conducted on diesel-powered, double-decker launches which chug between special island compounds where visitors may browse exhibitions on local flora and fauna, and stroll along fenced walkways lining the fringes of the mangrove forest. Crocodiles basking on the mudflats and deer grazing dhani grass at the water’s edge are a common sight, but your best chances of spotting a tiger will be if you catch one mid-stream, while swimming between islets in the river – the iconic sight of the Sundarbans.