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”.
The Manatee! A female sea cow can give birth to a single calf every three years. The calf begins feeding on plants when it’s a few weeks old, but continues to nurse from its mother for about 12 to 18 months. This long period of nursing allows the calf to learn migration routes, foods, and preferred feeding areas from its mother. As of April 2012, it is estimated there are less than 3,000 left, about ten percent die each year, injured and killed in accidents involving boats.
Info via: http://en.wikipedia.org/wiki/Manatee