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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.
Unlike those of manatees, the dugong's teeth do not continually grow back via horizontal tooth replacement. [38] The dugong has two tusks which emerge in males during puberty, and sometime later in life for females after reaching the base of the premaxilla. [33] The number of growth layer groups in a tusk indicates the age of a dugong. [39]
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.
In contrast, other marine mammals—such as whales, dolphins, porpoises, manatees, dugongs, and walruses—have lost long fur in favor of a thick, dense epidermis and a thickened fat layer (blubber) to prevent drag. Wading and bottom-feeding animals (such as manatees) need to be heavier than water in order to keep contact with the floor or to ...
The physiology of underwater diving is the physiological adaptations to diving of air-breathing vertebrates that have returned to the ocean from terrestrial lineages. They are a diverse group that include sea snakes, sea turtles, the marine iguana, saltwater crocodiles, penguins, pinnipeds, cetaceans, sea otters, manatees and dugongs.
Although cheek teeth are relied on for identifying species in other mammals, they do not vary to a significant degree among sirenians in their morphology, but are almost always low-crowned (brachyodont) with two rows of large, rounded cusps (bunobilophodont). The most easily identifiable parts of sirenian skeletons are the skull and mandible ...
The dugong (order Sirenia) is an endangered marine species that inhabits the waters of northeastern and northwestern Australia, particularly the Torres Strait. It can grow up to 3 metres (9.8 ft) long and weigh as much as 400 kilograms (880 lb). The dugong is the only herbivorous marine mammal in Australia, feeding on sea grass in coastal areas.