Manatees are large, peaceful aquatic animals that look like a cross between a hippopotamus and a seal. Manatees live along warm tropical or subtropical ocean shores and estuaries and in nearby rivers and freshwater lagoons. They are gentle, slow-moving, plant-eating mammals sometimes called “sea cows”.
Manatees have large, stocky bodies with short necks and blunt, oblong heads. They have gray-brown, mostly hairless, leathery skin. Manatees have broad snouts with sensory bristles on the upper lip. They have poor eyesight but good hearing and a very good sense of touch. A manatee’s body ends in a rounded paddle-like tail that it swings up and down to propel itself through the water. The manatee has two front flippers. Manatees grow to about 15 feet (4.6 m) long and weigh up to 3,500 pounds (1,600 kg).
Manatees are herbivores; they eat plants. They feed on seagrass, water hyacinths, and other aquatic plants but sometimes lift their heads above the water to feed on land plants growing at the water’s edge. Manatees use their large, rubbery, mobile upper lips to strip vegetation and grind it between their teeth. Manatees spend most of their time feeding. They eat about 8 percent of their body weight in plants each day. Manatees are one of only two marine animals that eat only plants (the other is their cousin the dugong). Manatees have very few competitors for food and so no natural predators.
When a manatee is not eating, it is usually resting or sleeping. Manatees sleep near the water’s surface or rest on the shallow bottom. Manatees are mammals so they must come to the surface to breathe every three to five minutes. When resting, a manatee can hold its breath and stay submerged for about 20 minutes.
Manatees are social animals. They live in small groups of about eight. Female manatees bear a single calf about every two years after about a year’s gestation. Manatees live for about 30 years.
Manatees belong to the order Sirenia. Early sailors once believed that manatees were mermaids or sirens of the sea; thus the name sirenians. Besides manatees, the other member of the order Sirenia is the dugong. Dugongs are found in the Indian Ocean and the southwestern Pacific Ocean and around the South Pacific Islands. Dugongs look much like manatees.
There are three species of manatee. The West Indian manatee (Trichechus manatus) is found from the Mid-Atlantic coast of North America, along coastal Central America to the northern coast of Brazil. The Amazonian manatee (Trichechus inunguis) is found in the Amazon River and its tributaries in South America. The West African manatee (Trichechus senegalensis) is found in coastal waters from Senegal to Angola in Africa as well as the major rivers in that region that empty into the Atlantic Ocean.