Brrr ... Manatees catch cold.

When winter rolls around, tourists flock to Florida's warm coastal waters. But for one giant bather--the Florida manatee--the sunshine state's winter waters simply aren't warm enough. In fact, when Florida's water temperature dips below 20[degrees]C (68[degrees]F), manatees can get skin lesions and infections, such as pneumonia, that eventually lead to death.

To stay healthy, Florida manatees used to migrate to warmer waters. But years ago, they stumbled upon winter retreats that are much closer to home: balmy outflows around Florida's power plants. Now 60 percent of Florida manatees bask in these "hot tubs" every winter.

But scientists are worried: Many of these power plants are aging and they have to be shut down. According to Gregory Bossart, a marine-mammal veterinarian at Florida's Harbor Branch Oceanographic Institution, "As the plants close, the manatees may be at risk of dying from cold-water-related illnesses." That's because manatees only have a thin layer of blubber, or fatty tissue, to keep warm. The blubber works as insulation--trapping heat, like a down jacket. But a manatee's blubber layer measures a measly 5 millimeters (0.2) inches). Compare that with a bottlenose dolphins, for instance, which is an 18 mm (0.7 in.)-thick layer!

Bossart recently discovered that with such thin padding, cool winter water slows the manatee's metabolism (chemical processes that fuel the body). Result: They have trouble digesting food and even stop eating. Without enough nutrients, these vegetarians become susceptible to deadly illnesses.

So what's a Florida manatee to do? Having gone years without migrating, many Florida manatees have lost the instinct to travel to warm waters and depend on the power plants to survive. Bossart suggests creating warm-water areas specifically for manatees. This way, even if a power plant closes, the manatees could continue to winter along Florida's coast--with all the tourists.

GENTLE GIANTS: Adult manatees grow to about four meters (13 feet) long and weigh 900 kilograms (2,000 pounds).

COZY CREATURES: Florida's coast isn't the only place to see manatees. They live at subtropical and tropical latitudes in warm coastal waters.

WINTER ESCAPE: More than 500 Florida manatees have been spotted snuggling in heated water of a single power plant.