Gangetic River dolphin
| Scientific Name | Platanista gangetica |  | |
| English Common Name | Gangetic River dolphin / Susu | ||
| Taxonomy | Class: Mammalia Order: Cetacea Sub-order: Odontoceti Family: Platanistidae Genus: Platanista Species: gangetica | ||
| Behaviour | Not a very acrobatic species and known to actively avoid all types of boats. They are usually relatively slow swimmers although they are capable of bursts of speed and able to change direction very quickly underwater. They also leave and re-enter the water very quickly and it can be difficult to actually sight the animal and not just the splash it leaves in its wake. Sometimes they can be seen swimming with their beaks sticking out of the water. They are normally found at junctions where two rivers meet, and just downstream of shallow water. They prefer deeper water, but can be found in water as shallow as a metre. Side-swimming is another feature of these dolphins and they usually employ this technique in shallow waters. They are also highly acoustic and are known to vocalize constantly – this may be connected to the fact that they are effectively blind, capable of seeing only shadows. Group size is generally small and consists of between 1 – 5 individuals. | ||
| World Distribution | Gangetic River dolphins are found in the Ganges, Meghna and Brahmaputra river systems of western India, Nepal, Bhutan, and Bangladesh and the Karnaphuli River, Bangladesh. There is discontinuous distribution from the foothills of the Himalayas to the limits of the tidal zone. During the dry season, when the river levels are low, they tend to stay in the main river channels and during the monsoon season, they move into creeks and tributaries. | ||
| Morphology | Although a different sub-species and geographically isolated from the Indus River dolphin, they look identical and display similar behaviour. Gangetic River dolphins are a uniform grey-brown colour. They have a stocky body with a slightly rounded belly and their forehead slopes sharply to a long, narrow beak that thickens towards the end; females tend to have longer beaks than males. Their front teeth are very long and extremely sharp and are visible even when the mouth is closed. They have a large number of teeth with between 52 – 78 on the upper jaw and between 52 – 70 on the lower jaw. Their flippers are very broad and paddle-shaped and their flukes are also very broad and wide relative to their body size. Instead of a prominent dorsal fin, they possess a small triangular-shaped hump, positioned towards the rear of the body. These are the only cetaceans that lack a crystalline eye lens, effectively making them blind and therefore they rely on a highly sophisticated echolocation system. | ||
| Threats | Due to their restricted habitat and proximity to human populations, these dolphins face a culmination of threats. These include; incidental entanglement in fishing gear, industrial development – including the construction of dams, vessel strikes, chemical and noise pollution and other human-induced habitat loss and degradation. Some individuals are also the victim of directed hunts, either due to perceived competition for food or for their liver oil which is used to attract commercially important species of fish. | ||
| Status | Formerly quite abundant, the overall population of Ganges river dolphins has been reduced to an estimated 4,000 - 5,000 individuals inhabiting the four major sections of the species' range. However, according to the IWC (2000) population assessments have generally been based on counts of dolphins on relatively small segments of rivers, with no estimates of precision. No comprehensive survey has yet been conducted throughout the species range. | ||
| Conservation Activities | CMS Appendix II IUCN – Endangered | ||
