They are also found in the river system of Bangladesh and India. The Ganges river dolphin has been recognized by the government of India as its National Aquatic Animal. [2] The Ganges river dolphin is primarily found in the Ganges and Brahmaputra Rivers and their tributaries in Bangladesh, India and Nepal, while the Indus river dolphin is found in the Indus River in Pakistan and its Beas and Sutlej tributaries. The oldest recorded animal was a 28-year-old male, 199 cm in length. Navigation and hunting are carried out using echolocation. TERMS OF USE 2nd Floor, Sector 67,SAS Nagar Taxonomists once considered the Ganges and Indus river dolphins a separate species while all other river dolphins were categorized under the Platanistidae family. This is as an ancient and peerless animal, and there is no species on earth today that resembles Platanista even closely. It is a trait shared by other freshwater species that have limited vision, such as the duckbilled platypus and Guiana dolphin. South Asian river dolphins use echolocation mostly in the mid-water sections for efficient propagation and reception, as they swim on their sides most of the time. It is listed on Appendix I[18] as this species has been categorized as being in danger of extinction throughout all or a significant proportion of their range and CMS Parties strive towards strictly protecting these animals, conserving or restoring the places where they live, mitigating obstacles to migration and controlling other factors that might endanger them. We do not understand much about the social lives of Platanista either. River dolphins are relatively small compared to other dolphins, having evolved to survive in warm, shallow water and strong river currents. Pyenson notes that some conservation biologists argue that the South Asian river dolphin should be prioritized for protection to preserve its evolutionary heritage. Chesapeake Testing provided X-ray scanning and support for digital-image processing. [19], Both subspecies have been very adversely affected by human use of the river systems in the subcontinent. Unfortunately, this also makes the species susceptible to fishing nets, as they can get entangled in fine monofilament gill nets, even drown and die. Photo: Dhritiman Mukherjee. +1 (425) 454-2113 IT C-7 KMG Tower Another wonderful instance of morphological adaptation is the fine vibrissae or hair on the snouts of calves, which are probably used for electroreception of shrimp and fish prey. This endangered species is threatened across its range by fisheries bycatch mortality, loss and fragmentation of riverine habitats by dams, hunting, pollution, and more recently, by the development of industrial waterways. Side swimming is an important adaptation, which is thought to allow the dolphins to orient according to the lighter surface of the water and the dark river bottom. [1] They can be most commonly found in water with high abundance of prey and reduced flow. The skull of Akrtocara yakataga rests on an 1875 ethnographic map of Alaska drawn by William Healey Dall, a broadly trained naturalist who worked for several US government agencies, including the Smithsonian, and honored with several species of living mammals, including Dall’s porpoise (, Extinct Prehistoric Species Is Relative of Endangered South Asian River Dolphin, May Offer Clues for Modern Conservation Scientists, James Di Loreto / Smithsonian Institution, Eliot Elisofon Photographic Archives, African Art, Assistant Secretary for Communications and External Affairs. South Asian river dolphins inhabit the Indus, Ganga, Brahmaputra, Meghna, and Karnaphuli-Sangu river basins of Pakistan, India, Nepal, and Bangladesh. [8] A small subpopulation can be still found on the Ghaghara River and possibly the Sapta Kosi River. Sexual dimorphism is expressed after females reach about 150 cm (59 in); the female rostrum continues to grow after the male rostrum stops growing, eventually reaching approximately 20 cm (7.9 in) longer. The Ganga River is an important and contiguous habitat for South Asian river dolphins. Boersma and Pyenson (2016). PeerJ. [5] In 1998, the results of these studies were questioned and the classification reverted to the pre-1970 consensus of a single species containing two subspecies until the taxonomy could be resolved using modern techniques such as molecular sequencing. The museum is open daily from 10 a.m. to 5:30 p.m. (closed Dec. 25). We need to listen to these clicks, which run like trains of cryptic Morse code, to understand its umwelt (experience of the environment). … The South Asian river dolphin feeds on a variety of shrimp and fish, including carp and catfish. © RoundGlass 2020, India RoundGlass Sustain is a media-rich resource on India’s natural world. It likely began with a gradual regression of the eye lens, and eventually, the eye-slits became pinholes that could detect only light from dark. Materialise provided technical support with 3-D model rendering. The majority of the Indus subspecies (P. g. minor) is located between the Sukkur and Guddu barrage in the Sind Province of Pakistan. It is an unusual creature that swims on its side, cannot see and uses echolocation to navigate murky rivers in Nepal, India, Bangladesh and Pakistan. The fossil, a partial skull about 9 inches long, was discovered in southeastern Alaska by Donald J. Miller, a geologist with the United States Geological Survey. The side swimming might also contribute to a “handedness” – much like humans tend to be right, or left-handed. [1] The Indus river dolphin is listed as endangered by the US government National Marine Fisheries Service under the Endangered Species Act. Fax: (202) 786-2982. The South Asian river dolphin (Platanista gangetica) is best described as a simple-minded dolphin, typically seen as a black blob on the water.Most observations of the species are from quick surfacing events, as they are completely invisible underwater in their sediment-rich riverine habitats. It is listed on Appendix II[18] as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements. The body of this mammal is long and plump, whereas the fins remind paddles by their shape. According to Nicholas D. Pyenson, the museum’s curator of fossil marine mammals, and Alexandra Boersma, a researcher in his lab, the fossil belonged to a dolphin that swam in subarctic marine waters around 25 million years ago. Platanista evolved in the murky, sediment-filled waters of the shallow Tethys Sea that was rapidly filling up as the Indian continental plate was colliding — and being sutured — with the Eurasian plate about 25 million years ago. 3911 (Dec. 12, 1969), pp. Arktocara yakataga, a new fossil odontocete (Mammalia, Cetacea) from the Oligocene of Alaska and the antiquity of Platanistoidea. The function of the caecum in this animal is probably for the digestion of chitin, a hard, proteinaceous material found in shrimp and prawn shells. To perceive the world of a visually limited species, we need to step out of our own reliance on the visual world. International trade is prohibited by the listing of the South Asian river dolphin on Appendix I of the Convention on International Trade in Endangered Species (CITES). The South Asian river dolphin—a species that includes both the Ganges river dolphin and the Indus river dolphin—is of great interest to scientists. But earlier this year, he and Boersma were captivated by and focused their attention on what Boersma calls “this beautiful little skull from Alaska.”.

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