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SOUTH ASIAN RIVER DOLPHIN
Platanista gangetica
Classification:
The classification of the South Asian river dolphin is hotly debated in scientific community.
it is thought to be the same species, the Indus bhulan and Ganges susu were listed as different species in 1971 due to differences in skull structure and blood proteins.
However this has never been fully accepted and now the two populations are spotted as subspecies of species Platanista gangetica; those found in Nepal, India and Bangladesh are listed as P.g. gangetica while those found in the Indus River in Pakistan are known as P. g. minor.
Appearance:
This dolphin has a special long thin beak with sharp pointed teeth.
The Proportionally longer in females than in males, the beak is designed for quick snap action to capture fast prey. It has a outstanding melon and, different then most cetaceans, the neck bone of the South Asian River dolphin are not fuse, allowing it to flexible its neck.
It has wide oar-shaped fin, a heavy body, a small triangle shape dorsal fin, and its fluke is wide with a pointed tips.
The colour of the South Asian river dolphin is changing, different from chocolate brown or yellowish-brownish to grey or pale blue, with the belly whiter than the rest of the body. The eyes are very small, short of a crystalline lens and are useless, though vision isn't very effective in cloudy estuary habitats.
They may be able to sense light brightness and the direction but can't not sense shapes.
Behaviour:
South Asian River dolphin are normally found alone or in pairs, and sometimes in small groups.
little is known about their behaviour as they try to be fast moving and very shy to boats.
P.g. gangetica's habit of surfacing at a light angle with its beak and head popping out of the water often it confused with the gharial, which is a type of crocodile also found in the Ganges River.
These dolphins gather in current pools near channel convergences, sharp meanders and human-built structures that cause similar effects.
These probably help to focus on their prey.
Other names:
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South Asian river dolphin
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Susu
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Bhulan
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Blind river dolphin
1.
Maximum length:
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Male: 2.2m
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Female: 2.6m
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Calf: 0.7m
2.
Maximum weight:
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Male: Unknown
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Female: 84 kg's
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Calf: Unknown
3.
Diet:
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Fish
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Invertebrates
4.
Estimated population:
4,000
5.
Distribution map:
Distribution:
P.g. gangetica is spotted in the Ganges-Brahmaputra-Meghna and the Karnaphuli-Sangu river and their tributaries, but the P.g.minor is found only in the Indus River.
Due to their habitats, both is being threatening by human activities (1) P.g.minor - Barrages or dams have separated their range, breaking up the population of the Indus susu. Much of its range is not able to life year round due to vary water levels and recent increases in demand for water and problems with cry season further reduce their range. In the dry season, many is trapped in irrigation canals.
Other threats such as habitat destruction and decay, entangle in nets and fishing gear, and pollution also.
P.g. gangetica - Although now it decreases, there is some illegal killing of Ganges river dolphins.
They are catched due to the fisheries competition, the value of their oil in traditional medicines, as bait, and food.
Other threats include increased growth of aquatic plants and chemical pollution. mainly dolphin is beening accidentally capture in fishing operations, especially gillnets.