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The dugong (/ ˈ d (j) uː ɡ ɒ ŋ /; Dugong dugon) is a marine mammal.It is one of four living species of the order Sirenia, which also includes three species of manatees.It is the only living representative of the once-diverse family Dugongidae; its closest modern relative, Steller's sea cow (Hydrodamalis gigas), was hunted to extinction in the 18th century.
Metaxytherium is an extinct genus of dugong that lived from the Oligocene until the end of the Pliocene. Fossil remains have been found in Africa, Europe, North America and South America. Generally marine seagrass specialists, they inhabited the warm and shallow waters of the Paratethys, Mediterranean, Caribbean Sea and Pacific coastline.
Dugongs are constrained in their feeding by their rudimentary dentition and limited nitrogen abundance in seagrasses. To counter this, they use a strategy called "cultivation grazing". This grazing can alter the composition of seagrass communities and favor species. Early and rapidly growing species will succeed over slow-growing species.
A fossil reveals how a now-extinct species of dugong was swimming in the sea about 15 million years ago when it was preyed upon by a crocodile and a tiger shark.
A humpback whale (Megaptera novaeangliae) A leopard seal (Hydrurga leptonyx). Marine mammals are mammals that rely on marine (saltwater) ecosystems for their existence. They include animals such as cetaceans (whales, dolphins and porpoises), pinnipeds (seals, sea lions and walruses), sirenians (manatees and dugongs), sea otters and polar bears.
Steller's sea cow (Hydrodamalis gigas) is an extinct sirenian described by Georg Wilhelm Steller in 1741. At that time, it was found only around the Commander Islands in the Bering Sea between Alaska and Russia; its range extended across the North Pacific during the Pleistocene epoch, and likely contracted to such an extreme degree due to the glacial cycle.
This is a list of North American mammals. It includes all mammals currently found in the United States, St. Pierre and Miquelon, Canada, Greenland, Bermuda, Mexico, Central America, and the Caribbean region, whether resident or as migrants. This article does not include species found only in captivity.
The manatee's tail is paddle-shaped, and is the clearest visible difference between manatees and dugongs; a dugong tail is fluked, similar in shape to that of a whale. The manatee is unusual among mammals in having just six cervical vertebrae , [ 11 ] a number that may be due to mutations in the homeotic genes . [ 12 ]