Irrawaddy dolphin

이라와디돌고래

The Irrawaddy dolphin has a rounded head with no beak and a small dorsal fin, and is blue-gray. It lives in coastal waters, estuaries and rivers of Southeast Asia and the Bay of Bengal, and some populations are critically endangered.

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At a glance

Class: Mammals
Lives in: Sundarbans coast, Bay of Bengal
Diet: Fish eater
Length: about 2.3 m
Conservation status: Endangered (IUCN EN)
Habitat: coasts, rivers & lakes

Quick answers

Where does the Irrawaddy dolphin live?

It lives in coasts, rivers & lakes of the Indian and Pacific oceans. On the globe you can find it near Sundarbans coast, Bay of Bengal.

How big is the Irrawaddy dolphin?

It grows to about 2.3 m.

What does the Irrawaddy dolphin eat?

Its diet: fish eater.

Is the Irrawaddy dolphin endangered?

It is listed as Endangered (IUCN EN).

The Irrawaddy dolphin, Orcaella brevirostris, is a slate-blue to grey dolphin with a high rounded forehead and no beak. It lives in scattered groups near sea coasts, in estuaries and in rivers around the Bay of Bengal and Southeast Asia, and it can live in salty, brackish and fresh water. The only large lagoon populations are in Chilika Lake in Odisha, India, and Songkhla Lake in southern Thailand.

Adults are about 2.3 metres long and weigh 90 to 200 kilograms, and the biggest recorded was a 2.75 metre male in Thailand. It looks like a beluga but is most closely related to the killer whale. It is very similar to the Australian snubfin dolphin, which was only described as a separate species in 2005. Some river populations are critically endangered.

A dolphin without a beak

The Irrawaddy dolphin has a blunt, rounded head, a small rounded dorsal fin set about two-thirds of the way back, and long, broad flippers. Its U-shaped blowhole sits slightly left of centre and opens forward, unlike any other dolphin. Each side of the jaw has 12 to 19 peg-like teeth.

It is a slow swimmer that surfaces with a roll and shows its tail only for a deep dive. It can squirt jets of water up to about 1.5 metres, sometimes while looking out of the water, which may help herd fish. It eats fish, squid and crustaceans, and groups of about seven can circle prey to trap it.

Where it lives

Besides coasts and estuaries, it has groups in freshwater rivers, including the Ganges, the Mekong and the Ayeyarwady, which gave it its name. Its range runs from the Bay of Bengal to New Guinea and the Philippines.

Counts are small: about 3,500 in coastal waters of the Bay of Bengal in Bangladesh, 156 in Chilika Lake in 2021, about 105 in a 190 km stretch of the Mekong in Cambodia in 2024, and about 70 in the Mahakam River in Indonesia. Sir Richard Owen described the species in 1866 from an animal found in Visakhapatnam in 1852.

Dolphins and fishers

Irrawaddy dolphins are usually shy of boats and do not bow-ride. In Myanmar, however, they have long helped fishers by herding fish toward their nets. In Brunei Bay some groups gather around fishing boats during the fishing season, from around December to February.

A mother has one calf, about 1 metre long and 10 kg, after a 14-month pregnancy, and weans it after two years. A dolphin may live about 30 years. Fishing nets, pollution and habitat loss are dangers for the small river and lagoon groups.

Fun facts

In Myanmar, Irrawaddy dolphins have long helped fishers by herding fish toward their nets.
Its blowhole opens to the front and sits left of centre, which no other dolphin has.
It looks like a beluga but its closest relative is the killer whale.
It can squirt water up to about 1.5 metres.
The snubfin dolphin was only recognised as a separate species in 2005.