Manatee, common name for each of three species of a large water mammal, popularly called a sea cow because it grazes on marine grasses and other water plants. The Amazonian manatee ranges throughout the Amazon River basin in South America; the West African manatee occurs in rivers and coastal waters of tropical West Africa; and the West Indian, or Caribbean, manatee is found in rivers and coastal waters from the southeastern United States and the Gulf of Mexico to the Caribbean Sea and northeastern Brazil. An adult manatee has a rounded body, usually colored light to dark gray or black, that tapers to a horizontally flattened, rounded tail. It is 2.5 to 4.5 m (8 to 14 ft) long, depending on the species, and weighs 200 to 600 kg (440 to 1300 lb). The small head includes a straight snout and a cleft upper lip with bristly hairs. Its nostrils, set on the upper surface of the snout, are closed tightly by valves when the animal is under water. The paddlelike forelimbs are set close to the head; no external hind limbs exist. Massive, heavy bones and long, narrow lungs, which extend through the entire body cavity, give the manatee evenly distributed buoyancy. A manatee cow gives birth about a year after mating; usually a single, pink calf is born.Manatees live in small family groups, although they occasionally travel in herds of 15 to 20. They feed in both freshwater and salt water, grazing for six to eight hours a day. An adult consumes an amount equal to between 5 and 10 percent of its body weight daily. Manatees have a slower metabolism than other mammals of similar size, which sharply reduces their energy requirements. This is especially important for Amazonian manatees when waters recede after floods, confining some for extended periods in shallow waters away from plants on river banks.
Manatees have few natural enemies because of their size. However, their population has been reduced significantly by heavy hunting for hides, meat, and blubber oil, and they are...
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