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Species Description

Manatee

Trichechus manatus


Species Image

Classification

Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Sirenia
Family: Trichechidae

Description

Uniformly grayish. Adults are 2.4 - 4.3 m (8 - 14 ft) in total length and weigh 272 - 1134 kg (600 - 2,500 lbs). These large, plump aquatic mammals are shaped somewhat like torpedos. The body is nearly hairless. There is no visible neck, front limbs are paddle-like, and the horizontal tail is broadly rounded. The small head is set off by a broad, square muzzle covered in thick bristles. The Manatee does not have a dorsal fin.

Life Cycle

The Manatee can breed year-round, and a single female may mate with several males. After a gestation period of 12 - 13 months, one calf (rarely two) is born, most frequently in the spring and summer months. A female Manatee produces a calf only once every 3 - 5 years. At birth, the pink-colored calf weighs 13.6 - 27.2 kg (30 - 60 lbs), and measures 1 - 1.2 m (3.3 - 3.9 ft) in total length. Immediately after birth, the female assists her baby to the surface where she supports it for about an hour. After this rest period, the calf begins to swim and come to the surface to breathe on its own. Calves nurse underwater and begin eating aquatic vegetation a few months after birth. They remain with the female for up to two years.

Natural History

This aquatic herbivore inhabits estuaries and brackish bays where large rivers enter the sea. The Manatee also lives in freshwater rivers and springs during winter months. It feeds mainly on submerged aquatic vegetation, and can eat 30 - 50 kg (66.1 - 110.2 lbs) of plant material a day. The Manatee prefers warm waters, for it has a slow metabolism and cannot tolerate water temperatures below 18 degrees C (65 degrees F). Colder temperatures drain its body heat and may cause death. The construction of power plants and industry in its winter range may be beneficial to this species because they provide warm-water discharges. The Manatee has a very gentle disposition and is harmless to humans. Snorklers and divers often swim with these shy creatures. Solitary in the warm months, Manatees congregate in herds of up to 50 or more in favorable wintering waters. Sharks, crocodiles, and the American Alligator are known predators of young Manatees. Adult manatees may live as long as 40 - 50 years.

Range

The Manatee migrates northward to coastal waters of South Carolina and Georgia in the summer. In the winter months, it moves back southward to the large spring-fed streams and rivers of central and southern Florida. The Manatee has been recorded along the Gulf Coast to the tip of southern Texas. It also occurs along the coasts of Mexico, Central America, the West Indies, Cuba, and the northern and eastern coasts of South America.

Conservation Status

This species is listed as Endangered by the Georgia and the U.S. Fish and Wildlife Service. The Manatee is protected from hunting, taking, or harassment of any kind.

Similar Species

Whales and porpoises have a horizontal fluke rather than the Manatee's rounded tail, and they are generally seen in deep water some distance from shore.