Dolphin Species: Irrawaddy
Orcaella brevirostris

Irrawaddy Dolphins inhabit the coasts and rivers of northern Australasia and southern Asia.

Classification
Sir Richard Owen first recognised this dolphin as a distinct species in the 1860s from a skull. While John Gray gave it the genus of Orcaella, Owen supplied the specific name, brevirostris ('short beak'). Although this species shows some characteristics of the dolphins, it looks more akin to the Beluga.

Local Names
Snubfin Dolphin; Pesut; Pesut Mahakam; Lumbalumba.

Description
The Irrawaddy Dolphin has a small, slightly curved dorsal fin and a tapered body. It has long flippers and its blowhole is set slightly to the left. The body colour is dark grey above, light grey below. There is no beak and the face can easily change expression. Like the Beluga, the head can move freely due to the fact that only two vertebrae are fused. The upper jaw has 17-20 pairs of teeth, the lower jaw, 15-18 pairs. Body length is between 2.15-2.75m, and weight is between 90-150kg.

Recognition at sea
The Irrawaddy Dolphin is slow-swimming and inconspicuous, likely to be confused only with the dugong or Finless Porpoise. In both cases, the fact that the Irrawaddy Dolphin has a dorsal fin should be enough for positive recognition.

Habitat
Irrawaddy Dolphins prefer warm, shallow coastal waters. Some have been found to inhabit freshwater rivers as far as 1300km from the sea.

Food & Feeding
Irrawaddy Dolphins seem to take fish dwelling in midwater and on the seabed. Squid and crustaceans may also be taken.

Behavior
The typical family unit contains up to 6 individuals, but occasionally can number around 15. Irrawaddy Dolphins have been spotted leaping, spyhopping and tail slapping. Only one mass stranding of three animals has been reported. They can be quite tame, and take well to captivity.

Longevity
Approximately 30 years.

Estimated Current Population
Unknown, but considered 'locally common'.

The Influence of Man
Irrawaddy Dolphins, because of their habitat, come into contact with man regularly. They are killed for food in a small area, but in northern Australia they often become entrapped in fishing nets. They are deemed as sacred by fishermen in Vietnam and Kampuchea.