Orcaella

Irrawaddy dolphin ( Orcaella brevirostris )

Orcaella is a genus of dolphins ( Delphinidae ). At the genus includes two species, the Irrawaddy dolphin ( Orcaella brevirostris ), which is found on the coasts of tropical Southeast Asia from the shores of the Bay of Bengal to the Great Sunda Islands, and the Australian Stupsfinnendelfin ( Orcaella heinsohni ), the east of it on the coasts New Guinea and northern Australia is located. The Stupsfinnendelfin was originally considered population of Irawadidelfins and was rewritten in 2005.

Features

Both dolphin species are about 2.70 meters long, are almost uniformly gray in color, with a lighter belly, without a beak-like snout elongated and resemble thus more porpoises ( Phocoenidae ). From Glattschweinswal ( Neophocaena phocaenoides ), which occurs in the same area as the Irrawaddy dolphin, the latter can be distinguished by the presence of a small fin that lacks the Glattschweinswal.

The head profile of both species is rounded and is characterized by the large, round melon. The corners of the mouth are bent so that the impression of a " smile " is created. Head and body are often separated by a conspicuous neck furrow.

The fin of both species sits on the center back, is strong but not particularly high. In both species Orcaella the trailing edge of the fin is often damaged. The flippers are spatulate, curved front edge, rounded off the top. The Fluke is small, notched at the concave trailing edge in the middle and has pointed ends.

Way of life

While the coastal Stupsfinnendelfin found only in the sea, the Irrawaddy dolphin lives in fresh water and has been in the Irrawaddy 1500 km upstream and 690 km in the Mekong encountered from the mouth. In Kalimantan, there are inland populations in rivers and lakes over 500 km. Both species live in small groups, are shy and compared with other dolphins not particularly active animals.