| Irrawaddy Dolphin | |
|---|---|
 | |
| Scientific Classification | |
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Mammalia |
| Order | Cetacea |
| Family | Delphinidae |
| Genus | Orcella |
| Species | Orcella Brevirostris |
| Conservation Status | |
 Endangered | |
The Irrawaddy Dolphin (Orcaella brevirostris) is a species of dolphin native to Southeast Asia. It's aliases include Irrawaddy river dolphin, though it does not fully dwell in rivers.
Taxonomy[]
Appearance[]
They are somewhat similar to a Beluga in appearance, but are actually related to Killer Whales. It has an enormous melon and a very blunt head, which makes the beak not prominent at all. It's dorsal fin is close to it's tail. It is short and blunt. It's flippers are very long and broad. It is primarily white throughout, but is more white on the underparts. Irrawaddy dolphins usually are 7.5-9 feet long and weigh 290 lbs.
Habitat and Sup-populations[]
Although sometimes called the Irrawaddy river dolphin, it is not a true river dolphin, but an oceanic dolphin that lives in brackish water near coasts, river mouths, and estuaries. It has established subpopulations in freshwater rivers, including the Ganges and the Mekong, as well as the Irrawaddy River from which it takes its name. Its range extends from the Bay of Bengal to New Guinea and the Philippines, although it does not appear to venture off shore. It is often seen in estuaries and bays in Borneo Island, with sightings from Sandakan in Sabah, Malaysia, to most parts of Brunei and Sarawak, Malaysia. A specimen was collected at Mahakam River in East Kalimantan.
Presence of the species in Chinese, Taiwanese, and Hong Kong's waters has been questioned as the reported sightings have been considered unreliable, and the easternmost of ranges along Eurasian continent is in Vietnam.
No range-wide survey has been conducted for this vulnerable species; however, the worldwide population appears to be over 7,000. In India, Irawaddy dolphins are mostly found in Chilika Lake. Known subpopulations of Irrawaddy dolphins are found in eight places, listed here in order of population, including conservation status.
Mating[]
A female or male dolphin will attempt to pursue a mate for about a few minutes. They intertwine facing their bellies together and begin to copulate for 40 seconds. Once copulation has occurred, the dolphins will break away from each other and set off in different directions.
Behavior[]
Irrawaddy dolphins communicate with clicks, croaks, and various other sounds that's maximum frequency is 60 kilohertz. It might use these sounds as echolocation. Inspection of the feasting in captive specimens has lead scinetists to believe that tese animals take in food using suction. This suits, considering it is commonly seen during spy-hopping spitting water from it's mouth high in the air to expel water taken in during feeding.
Irrawaddies are typically slow swimmers, but speeds recorded up to 15 miles per hour were recorded when it was being pursued. They surface in a rolling manner then lift their tail vertically in the air and dive down deep to hunt. They can hold their breath for 12 minutes. When they surface again, they may make low leaps above the surface. Groups of six dolphins is common, but 15 dolphins have been seen at one time. Irrawaddy dolphins seem scared of other species. Irrawaddies and humbback dolphins were caught and kept in the same tank. The humpbacks chase the Irrawaddies around and confined them to a tiny portion of the exhibit.
Irrawaddie's gestation is typically 14 months. Cows give birth to a young every 2-3 years. When they are born, they weigh 22 lbs and are 3.3 feet long.
Irrawaddies have a mutualistic relationship with people. Local fishermen report that they will help them drive the fish into their nets based on a signal given by the men. The dolphins will eat whatever fish escaped.
Diet[]
Fish eggs, fish, cephalopods, and crustaceans are their primary source of food.
Lifespan[]
They live for usually 30 years.
Distribution[]
Irrawaddies live in bays, estuaries, river mouths, coastal lines, and sometimes rivers such as the Mekong, Ganges, and Irrawaddy. They are found in Bangladesh, India, Indonesia, Thailand, Burma, Philippines, Laos, Cambodia, New Guinea, Malaysia, and in some regions near Australia and New Zealand, where it is often confused for the Snubfin dolphin.
Conservation[]
Places outside of Bangladesh and India, it is a critically endangered species due to gillnets, crabnets, electrofishing, dam building, blastfishing, and gold mining. It is commonly caught for shows, entertainment, and for casinos, theme parks, and many other reasons that severely affect the dolphin. They were once hunted for their oil.
Many, many efforts have been taken to save this species, both national and international. Some successful, some not. For now, this species is still protected, but accidental murders still happen.
Gallery[]
Photos[]
Videos[]
Irrawaddy Dolphin (Orcaella brevirostris)
Quick video