They are usually encountered on their own or in loose aggregations; the dolphins do not form tight interacting groups. Photos: The Children’s Museum of Indianapolis CC BY-SA 3.0 (left), Mayukh Dey (right). Since it is almost blind, Platanista constantly emits high-frequency clicks (nearly 24×7) to navigate, feed, and, communicate with others of its kind. [12] Occasionally, individuals swim along with their beaks emerging from the water,[14] and they may "breach"; jumping partly or completely clear of the water and landing on their sides.[14]. Smith, B. D., G. T. Braulik and R. K. Sinha (2004). But earlier this year, he and Boersma were captivated by and focused their attention on what Boersma calls “this beautiful little skull from Alaska.”. The relatively high proportion of shrimp in calves’ diets indirectly supports this possibility. Conservationists often attach purpose to evolution, as if these waters and land masses conspired to create this particular animal, but that is not quite right. Rep. Whales Res. Pyenson notes that some conservation biologists argue that the South Asian river dolphin should be prioritized for protection to preserve its evolutionary heritage. “Considering the only living dolphin in this group is restricted to freshwater systems in Southeast Asia, to find a relative that was all the way up in Alaska 25 million years ago was kind of mind-boggling,” Boersma said. To perceive the world of a visually limited species, we need to step out of our own reliance on the visual world. They have also produced a digital three-dimensional model of the fossil that can be explored at The species does not have a crystalline eye lens, rendering it effectively blind, although it may still be able to detect the intensity and direction of light. 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. Most observations of the species are from quick surfacing events, as they are completely invisible underwater in their sediment-rich riverine habitats. Mohali – 160062, Punjab, United States There is scattered information, available from observing captive individuals kept in research facilities in Switzerland, Japan, and the USA in the 1970s, but we cannot be sure that these behavioural records represent wild populations. [19], Both subspecies have been very adversely affected by human use of the river systems in the subcontinent. Inst., 24: 87-108, Museo di storia naturale e del territorio dell'Università di Pisa, File:Ganges and Indus river dolphin size.svg, File:Cetacea range map Indus and Ganges River Dolphin 2.png, Convention on International Trade in Endangered Species, Convention on the Conservation of Migratory Species of Wild Animals, Creative Commons Attribution-ShareAlike 3.0 Unported License, The New Book of Knowledge, Grolier Incorporated, "South Asian river dolphin (Platanista gangetica)", Science, New Series, Vol. The teeth of young animals are almost an inch long, thin and curved; however, as animals age, the teeth undergo considerable changes and in mature adults become square, bony, flat disks. TERMS OF USE The Indus River dolphin is found in the Indus River of Pakistan. Arktocara yakataga, a new fossil odontocete (Mammalia, Cetacea) from the Oligocene of Alaska and the antiquity of Platanistoidea. In spite of these interesting behaviours, Platanista’s acoustic complexity, while suited to its lifestyle, does not match “modern” and highly social dolphins, such as the famous bottlenose dolphins. Getting such a picture of this elusive river dolphin is rare, as the species does not stay at the surface for very long. [11], Births may take place year round, but appear to be concentrated between December to January and March to May. They are also found in the river system of Bangladesh and India. Past investigations on captive Platanista also suggest that it might be coprophagous, i.e. [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. You can read more about his work here: 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. “Knowing more about this fossil means that we know more about how that divergence happened.”. But human activities, including the use of fishing nets, pollution and disruption of its habitat, have decimated the species to only a few thousand remaining individuals. Bellevue, WA 98004. Platanista gangetica species guide - the South Asian River dolphin in found the Indus and Ganges River systems. The museum’s researchers, scientific collections, free exhibitions and educational programs address fundamental questions, spark curiosity and illuminate the beauty and wonder of the planet. The species has only a small, triangular lump in the place of a dorsal fin. In addition, the animal can be easily identified by having a ridge on its back instead of a dorsal fin. They range in size from the 5-foot (1.5 m) long South Asian river dolphin to the 8-foot (2.4 m) and 220-pound (100 kg) Amazon river dolphin.Several species exhibit sexual dimorphism, in that the males are larger than the females. The South Asian river dolphin (Platanista gangetica) is best described as a simple-minded dolphin, typically seen as a black blob on the water. [10] Mature females are larger than males. “One of the most useful ways we can study Platanista is by studying its evolutionary history, by looking at fossils that are related to it to try to get a better sense of where it’s coming from,” Boersma said. Platanista gangetica minor, The South Asian river dolphin (Platanista gangetica) is a freshwater or river dolphin found in India, Bangladesh, Nepal and Pakistan which is split into two subspecies, the Ganges river dolphin (P. g. gangetica) and Indus river dolphin (P. g. 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. an animal that eats its own faeces to make up for its limited digestive capacity. It is a captivating reminder of the mysterious ecological sphere around us: a world we understand so little about, but are so indifferent to destroying. minor). With more than 40 million specimens in the museum’s Department of Paleobiology, “We are always learning new things about the vast legacy built by our predecessors at the museum,” Pyenson said. We are just beginning to understand how Platanista works. It is improbable that the river dolphins made it from one river to another through the sea route since the two estuaries are very far apart. How does a mother communicate with its calf? Irrigation has lowered water levels throughout both subspecies' ranges. Some information on the growth of the Ganges dolphin with a comment on the Indus dolphin. In this way, the loss of an important sensory perception appears to have helped Platanista remain resilient, and its ability to persist in a riverine environment intensely abused by humankind is proof. The two subspecies are geographically separate and have not interbred for many hundreds if not thousands of years. A fossil that has been in the collection of the Smithsonian’s National Museum of Natural History since it was discovered in 1951 is today helping scientists piece together the evolutionary history of whales and dolphins, including the origins of the endangered South Asian river dolphin. One of the lines being versed from Valimiki’s Ramayan, highlighted the force by which the Ganges emerged from Lord Shivji’s locks and along with this force came many species such as animals, fish and the Shishumaar—the dolphin. That makes Platanista a proverbial chimera: a dolphin overall, but with physiology that is intimately connected to its once populous ancestors, which resembled hippopotami, deer, and pigs. [4] Until the 1970s, the South Asian river dolphin was regarded as a single species. In Platanista it was measured at less than one per cent. [17] The proposed conservation measures include designated dolphin sanctuaries and the creation of additional habitat. Artistic reconstruction of a pod of Akrtocara yakataga, swimming offshore of Alaska during the Oligocene, about 25 million years ago, with early mountains of Southeast Alaska in the background. The majority of the Indus subspecies (P. g. minor) is located between the Sukkur and Guddu barrage in the Sind Province of Pakistan. … According to Land of the Seven Rivers: A Brief History of India's Geography by Sanjeev Sanyal, a likely explanation is that several north Indian rivers like the Sutlej and Yamuna changed their path in ancient times and carried the dolphins with them. The flippers and tail are thin and large in relation to the body size, which is about 2-2.2 meters in males and 2.4-2.6 m in females.