Science Fair Project Encyclopedia
Trichechus senegalensis Manatees (family Trichechidae, genus Trichechus) are large aquatic mammals sometimes known as sea cows. The Trichechidae differ from the Dugongidae in the shape of the skull and the shape of the tail. Manatees' tails are paddle-shaped, while the Dugong's is forked. It is an herbivore, spending most of its time grazing in shallow waters.
One species (the West African Manatee Trichechus senegalensis) inhabits the west coast of Africa, another (the Amazonian Manatee T. inunguis) inhabits the east coast of South America, and a third (the West Indian Manatee T. manatus) the West Indies in the Caribbean Sea. The Florida Manatee is by some considered a distinct species, but ITIS treats it as a subspecies of T. manatus, and this is now usual. It can reach 4.5 meters (15 feet) or more in length, and lives both in fresh and salt water. It was once hunted for its oil and flesh but is now legally protected.
The West Indian Manatee is an endangered species. Although it does not have any natural predators, human expansion has reduced its natural habitat in the coastal marsh areas and many manatees are injured by the propellers of outboard motor boats. Manatees will often ingest fishing gear (hooks, metal weights, etc.) during feeding. These foreign materials do not seem to harm manatees, except for monofilament line or string. This can get clogged in the animal's digestive system and slowly kill the animal.
Manatees often congregate near power plants, which warm the waters. Some have become reliant on this source of unnatural heat and have ceased migrating to warmer waters. Some power plants have recently been closing and the U.S. Fish and Wildlife Service is trying to find a new way to heat the water for these manatees.
The main water treatment plant in Guyana has three manatees whose job it is to keep storage canals clear of weed.
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