Trichechus manatus manatus.
Manatees (family Trichechidae, genus Trichechus) are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living species in the order Sirenia: the Amazonian manatee (Trichechus inunguis), the West Indian manatee (Trichechus manatus), and the West African manatee (Trichechus senegalensis). They measure up to 13 feet (4.0 m) long, weigh as much as 1,300 pounds (590 kg), and have paddle-like flippers. The name manatí comes from the Taíno, a pre-Columbian people of the Caribbean, meaning "breast". Contents [hide]
Manatees inhabit the shallow, marshy coastal areas and rivers of the Caribbean Sea and the Gulf of Mexico (T. manatus, West Indian manatee), the Amazon Basin (T. inunguis, Amazonian manatee), and West Africa (T. senegalensis, West African manatee). West Indian manatees enjoy warmer waters and are known to congregate in shallow waters, and frequently migrate through brackish water estuaries to freshwater springs. They cannot survive below 15°C (60°F). Their natural source for warmth during winter is warm, spring-fed rivers.
Manatees have a mass of 400 to 550 kilograms (880 to 1,200 lb), and mean length of 2.8 to 3.0 metres (9.2 to 9.8 ft), with maxima of 3.6 metres (12 ft) and 1,775 kilograms (3,910 lb) seen (the females tend to be larger and heavier). When born, baby manatees have an average mass of 30 kilograms (66 lb). They have a large, flexible, prehensile upper lip. They use the lip to gather food and eat, as well as using it for social interactions and communications. Manatees have shorter snouts than their fellow sirenians, the dugongs. Their small, widely-spaced eyes have eyelids that close in a circular manner. The adults have no incisor or canine teeth, just a set of cheek teeth, which are not clearly differentiated into molars and premolars. Uniquely among mammals, these teeth are continuously replaced throughout life, with new teeth growing at the rear as older teeth fall out from farther forward in the mouth. At any given time, a manatee typically has no more than six teeth in each jaw of its mouth. Its tail is paddle-shaped, and is the clearest visible difference between manatees and dugongs; a dugong tail is fluked, similar in shape to a that of a whale. Like horses, they have a simple stomach, but a large cecum, in which they can digest tough plant matter. In general, their intestines have a typical length of about 45 meters, which are unusually long for animals of their size.