SIREN SONG

In Brazil, Amazonian manatees are poached for their porklike meat and thick hides. From Australia to Kenya, dugongs are being entangled in anti-shark or fishing nets and drowned. In the Persian Gulf, they died in late 1983 as a result of major oil spills and leakage. In the United States, Florida's exploding human population has filled in and polluted much of the West Indian manatee's habitat; the remaining open areas are dangerous because of boats that crash into the animals or lacerate the backs of these slow-moving aquatic mammals with propellers. Other major threats to manatees are cold temperatures and toxic algal blooms. Although the manatee is honored as the state marine mammal, its numbers have plummeted from an estimated 10,000 to just over 2,000 in 1996. The only cold-water Sirenian, the now-extinct Steller's sea cow, was the largest of the order, reaching lengths of 25 feet and weighing up to seven tons. Discovered in 1741 by explorer Vitus Bering's ship-wrecked crew some 100 miles east of Siberia in the Bering Sea, the species was wiped out within 27 years by Russian hunters.

Today, survivors of the order Sirenia are still elusive. Accurate counts and ranges for most dugongs and manatees are not available. It is known that the West Indian manatee is found in rivers and coastal areas of the tropical and subtropical Atlantic, but populations other than Florida's are so small that there is virtually no information about them. The Florida manatee can grow to be 8-14 feet long and weigh 2,000 pounds. It consumes 5-10 percent of its body weight in aquatic plants daily and spends most of its life either eating or resting. Manatee females bear a single calf every two to three years,  so it takes a long time to replace a manatee that dies. Mother and calf stay close together for one to two years.

Manatees are sometimes found in fairly large groups of ten to fifty. They touch each other a lot and will touch humans, too. Curious and even friendly, they will approach people voluntarily, coming close enough for a pat on the back or rolling over for a tummy rub. Sometimes manatees gather below partially open sluice gates, where the current is strong, for what researchers call "body surfing." In sessions that may last over an hour, the animals repeatedly ride the current downstream in parallel formation, then work their way back up. Variations include the entire group riding sideways to the current, or moving diagonally across it, with manatees frequently nuzzling and vocalizing between rides.

For every fact gleaned about Sirenians, there are surely a thousand more to be learned. There is also no doubt that at the rate they are declining, dugongs and manatees may follow the Steller's sea cow into oblivion before we have begun to understand them.

MANATEE FACTS
Proper Name	The Florida manatee is Trichechus manatus.
Size	A manatee usually weighs about 1,000 pounds. (Baby manatees weigh about 45 pounds.)
Life span	Not known for sure but it may be about 50 years.
Habitat	Coasts of the Atlantic Ocean and the Caribbean Sea from the southeastern US through northeastern Brazil and along the central African shore. Their cousins, the dugongs, are found in the Indian and Pacific Oceans from northern Australia to the Arabian Gulf.
Food	Plants, especially water hyacinth.
Bonus fact	A manatee can hold its breath for about 16 minutes and normally breathes about once every 90 seconds.