Sundarbans Mangrove Forest

The Sundarbans is the largest mangrove forest in the world, spread across the delta of the Ganges, Brahmaputra and Meghna rivers in south-west Bangladesh and neighbouring West Bengal, India. About 6,000 km² lies in Bangladesh and is visited only by boat with a Forest Department permit, which suits wildlife and birding travellers with one to three days.

The forest lies where the three great rivers meet the Bay of Bengal. Once about 16,700 square kilometres, the Bangladesh part now covers about 6,000 square kilometres in Khulna Division, and the rest extends into West Bengal, India. It is a maze of tidal rivers, creeks and low islands that flood twice a day. The name is usually traced to the sundari tree, Heritiera fomes, the most common mangrove here.

Over the past two centuries large areas on the northern edge were cleared for farming and settlement. The colonial government declared the remaining forest a reserve in 1875, and after the partition of 1947 about two-thirds of it fell within what is now Bangladesh. Three wildlife sanctuaries in the west, south and east of the Bangladesh forest were inscribed by UNESCO as a World Heritage Site in 1997, and the Sundarbans Reserved Forest is also a Ramsar wetland of international importance.

The trees have special breathing roots, called pneumatophores, that poke up through the mud to take in air at low tide. Besides sundari, the forest holds gewa, goran and keora trees and nipa palm, which villagers collect for roofing. Honey gatherers, called mouals, enter the forest under Forest Department permits, mostly between March and May, and before setting out they pray to Bonbibi, the forest goddess believed to protect them from tigers.

A camera-trap survey released in October 2024 counted at least 125 adult Bengal tigers on the Bangladesh side, up from 106 in 2015. The forest is also home to chital deer, rhesus macaques, wild boar, saltwater crocodiles and about 320 species of resident and migratory birds. Ganges river dolphins use the larger channels, and Irrawaddy dolphins, an estuarine species, live in the brackish waters near the coast. Popular stops on boat trips include Karamjal near Mongla, Harbaria, Kotka and Kochikhali.

All visits are by boat with a Forest Department permit, and most visitors join a licensed tour operator who arranges the permit, forest guards, meals and cabins. Day trips from Mongla reach the forest edge, while two to four day cruises go into the sanctuaries. The best months are from November to February, when the weather is cool and dry; the monsoon brings rough water, and the forest closes to tourists from 1 June to 31 August for the wildlife breeding season.

Boats leave from Mongla and Khulna. Mongla is about an hour by road from Khulna, which has the better rail and bus links, and Jessore Airport, about two hours from Khulna, has domestic flights. On shore, visitors walk only with a forest guard. Access involves muddy jetties and stepped watchtowers, so the trip does not suit wheelchair users.