May 11, 2000

Searching for Manatees
Manatee
A narrow river winds its way along the Florida coast to the Gulf of Mexico. The water is murky brown from the run-off of the mangrove trees. Shore birds on delicate legs feed along the bank. Four kayakers, paddles in their laps, sit quietly, straining to focus on a bend in the river. "Look!" says one with a gasp of delight, and they turn to see what she sees, a swirl of water and a lazy roll—the great gray-brown torso of an elusive Florida manatee.

And, herein lies the problem.

If idling kayakers find manatees hard to spot, then the more than 830,000 registered boaters who speed across Florida's waterways find them even harder to see—and avoid. In 1999, boats and other forms of human activity were cited in 45% of the 268 recorded manatee deaths. And manatees are already dying at record numbers this year. Only 3,000 remain in the United States.

The Sirens of Yesterday?

There is a mystery associated with manatees. Were these creatures the Sirens of Greek myths? They carry the scientific name Sirenia for this reason. It's hard to believe that a sailor, even after months at sea, could mistake these creatures for the dangerous half-woman, half-bird whose seductive song would lure a sailor to his death. But manatees captured the popular imagination of explorers and sailors of old. Upon first seeing manatees (or possibly sea lions) in the Caribbean, Columbus wrote that these "mermaids were not half as beautiful as they are painted." Jacques Cousteau, the pioneering French underwater explorer, made a television program some years ago about manatees entitled, "Forgotten Mermaids" and only added to the lore.

These bewhiskered animals with the gentle temperament and no known defenses, have no enemies except for humans. A cousin, the Stellar sea cow, was hunted to extinction just 27 years after it was discovered in the Bering Sea in 1741. Now manatees and their relatives, the dugongs, are endangered around the world.

In some places, manatees are hunted for food, but in Florida, the story is more complex: Loss of habitat from development along the coast, a low rate of reproduction, and a high death rate from encounters with people are the main reasons that biologists fear for the manatees' future.

Did You Know?
Manatees...

  • are entirely aquatic. They evolved from four-footed land mammals more than 60 million years ago. Their closest relatives are elephants and hyraxes, small mammals native to Asia and Africa.

  • range in color from gray to brown, and the average adult is about 10 feet long and weighs between 1,200 and 1,800 pounds. Florida manatees belong to the West Antilles manatee family.

  • live in fresh water, brackish, and marine habitats, but need access to freshwater to survive.

    Manatee at surface
  • spend six to eight hours a day feeding and may consume as much as 100 pounds of sea grass in that time.

  • feed entirely underwater.

  • look fat but have very little body fat. The gut tract takes up a large percentage of their bodies. This also means that they are temperature-dependent, preferring water warmer than 68° Fahrenheit (although adults can survive at temperatures as low as 55°).

  • reproduce as early as 4 to 5 years of age. Manatees may breed throughout their lives, but they are not fast reproducers: Gestation takes about 13 months.

  • have newborns that range in size from 4 to 4.5 feet, and weigh about 60 pounds. Calves are dependent on their mother for up to 2 years. They nurse underwater and form a close bond. Mother and calf form the principal manatee social unit.

  • move slowly most of the time but can be quite playful. They can execute barrel rolls, somersaults, and other acrobatic tricks. They tend to be solitary, except in mating season and when they congregate in warm-water refuges in winter. Underwater photographers who have spent time with manatees say they are curious and friendly.

Out of Step, Out of Time
"The sad fact about manatees," notes Dr. Steven Bortone, a marine biologist and environmental director of the Conservancy of Southwest Florida in Naples, is that "manatees are simply victims of circumstance. They are big and slow, and they just don't fit in with modern humans. No one purposefully wants to get rid of manatees; they're just in the way. And we don't know what to do with them."

Manatees feedingAs people move to Florida—1,000 people migrate each day—many of them take up residence along the coasts, buy boats, and set out to have fun on the water. Manatees must compete against people for the same coastal habitat.

Since these animals must come to the surface to breathe, they are vulnerable to collisions with boats. Researchers say manatees can detect the presence of boats, but can't swim fast enough to get out of harm's way. If the manatee does not die in the encounter, it will be scarred or injured. In fact, the Sirenia project of the U. S. Geological Survey identifies and tracks more than 1,000 manatees by their scars.

"Manatees are a good example of how people can mess up the natural world in part by not thinking ahead," says Dr. Daniel K. Odell of Sea World in Orlando and the co-author of Manatees and Dugongs.

"If we can't take care of the manatees, than what hope do we have for the rest of our environment?"

The conflict between humans and manatees is an example of two species competing for the same resources. Check out the activities:

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Saving Manatees
For all these reasons, many Florida residents are fighting to save manatees. They want to enforce safe speed limits for recreational motorboats. They are seeking propeller guards for larger tugboats and freighters. Though these boats travel slowly, their large propellers can easily suck in a manatee.

Manatee advocates also recommend creating sanctuaries and refuges to protect manatees that are resting, feeding, and breeding. Save the Manatee Club and a national coalition of 19 environmental and animal protection groups have also filed two federal lawsuits demanding changes in how the federal government and the state of Florida protect endangered animals. They charge these institutions with failing to protect the manatee and other threatened creatures.

As Dr. Odell noted, the manatee has had to adapt to us, can we adapt to the manatee?

  • How do you think we could live together with manatees? What kind of changes would you make to create an environment that works for manatees and people?

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