Threatened species of freshwater dolphins River dolphins under threat of extinction
This family includes 5 species in 4 genera. In many accounts of cetaceans, its members are placed in four separate families: Iniidae (South American river dolphin), Lipotidae (Chinese river dolphin), Platanistidae (Indian river dolphins), and Pontoporidae ( La Plata river dolphin). Members of these families are found in fresh-water rivers and coastal waters in Asia and South America. These dolphins are generally small, ranging from 1-3 m in length and from roughly 20 to 225 kg in weight, depending on species. They have a long, slender beak, above which rises a sharply differentiated, bulging forehead. The eyes are small, and in some species, appear atrophied. Unlike most other cetaceans, platanistids have a distinct neck. The flippers are broad and either rounded or sharply curved. The dorsal fin is low in all but the La Plata dolphin, in which it is moderately high. Colors tend to be muted grays, pinks, and browns, usually darker above and paler below. The rivers used by most platanistids are muddy, and these animals probably rely on echolocation more than vision to locate their prey. They feed on fish and invertebrates, making dives that rarely last more than a few minutes. Group size varies from single individuals to 10 or 12. In general, little is known about their ecology and social behavior.
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