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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.
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]
Dugong skeleton displayed at Philippine National Museum. Dugongidae's body weight ranges from 217 to 307 kg for juveniles, 334 to 424 kg for subadults, and 435 to 568.5 kg for adults. Oral temperatures for individual dugongs is determined from 24° to 34.2 °C. Heart rate readings are from 40 to 96 bpm and vary between individual dugongs.
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 wide variety of seagrass has been found in dugong stomach contents, and evidence exists they will eat algae when seagrass is scarce. [74] West Indian manatees eat up to 60 different species of plants, as well as fish and small invertebrates to a lesser extent. [75]
The family has one surviving species, the dugong (Dugong dugon), one recently extinct species, Steller's sea cow (Hydrodamalis gigas), and a number of extinct genera known from fossil records. Subcategories
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]
They are commonly found attached to sharks, manta rays, whales, turtles, and dugongs, hence the common names "sharksucker" and "whalesucker". Smaller remoras also fasten onto fish such as tuna and swordfish , and some of the smallest remoras travel in the mouths or gills of large manta rays, ocean sunfish , swordfish and sailfish .