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or sea cow,
name for a large aquatic mammal of the order Sirenia. Living sirenians are the dugong and the manatee, both found in warm, shallow waters in sheltered regions, where they feed on seaweeds and seagrasses.
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any one aquatic mammal of the family Manatidae of the order Sirenia. The body, which usually measures 4 m long (rarely 5 m) and weighs 360 kg (rarely 600 kg), is spindle-shaped. The fin is horizontal and rounded. There are no external ears or hind limbs; the forelimbs have been converted into flexible pectoral fins with three vestigial claws. The coloration of the hairless body ranges from light to dark gray. The fleshy upper lip is cleft and very mobile, with each half moving independently. The paired nostrils are at the tip of the thick muzzle and open only at the moment of inhalation or exhalation. There are approximately 20 teeth. The incisors are lost early, and in their place develop horny plates that serve to grasp and grind food. Manatees feed on aquatic vegetation found in shallow waters.
There are three species of manatees. The Florida manatee (Trichechus manatus) lives along the coasts from Florida to Brazil, Nalterer’s manatee (T. inunguis) is found in the Amazon and Orinoco rivers and their tributaries, and the West African manatee (T. senegalensis) lives in the coastal waters and rivers of equatorial Africa.
The gestation period of manatees is five to six months. A single young is born, measuring about 1 m long and weighing 16 to 27 kg; it is nursed by its mother for 18 months. Manatees reach sexual maturity at three to four years of age, when the body is 2.5 m long. In cold weather the animals congregate in groups of up to 15 to 20 individuals. Often resting during the day on the surface of the water, they are most active in the evening, at night, and in the morning. They generally dive and remain underwater for one or two minutes (maximum, 16 minutes). Manatees live in captivity but reproduce poorly. Owing to the sharp decrease in their numbers, trading in manatees has been prohibited in the USA since 1893 and in Guyana since 1926.
REFERENCESZhizn’ zhivotnykh, vol. 6. Moscow, 1971.
Mohr, E. Sirenen oder Seekuhe. Ziemsen, 1957. (Die Neue Brehm-Bucherei.)