CRYSTAL RIVER, Fla. (AP) — Like most sensible creatures, manatees — the sea cows that live in the waters around Florida — seek warmth when it's cold.

On Thursday morning, roughly 500 of the gentle, aquatic giants crowded into the Three Sisters Springs as temperatures along Florida's Gulf Coast dipped below 50 degrees.

"They're basically chilling in the springs sleeping," said Ivan Vincente, visitor services specialist for the U.S. Fish and Wildlife Service at Crystal River National Wildlife Refuge. "They're spending the vast majority of the time resting and conserving energy."

Not a bad way to spend the winter.

Vincente said this year is unusual because the manatees arrived at the springs about 60 miles north of Tampa in January and have camped out there for weeks because of the cold. The springs have been periodically closed to swimmers because of the large concentration of the endangered animals — but that hasn't stopped visitors from flocking to the boardwalk to gawk at the behemoths, which can weigh up to 1,300 pounds.

"Awesome. It's just a wonderful creature," said Jody Shifflette, a manatee lover who recently moved from West Virginia to Florida." I think a lot of people don't think about them. You see your deer and your fish and things like that, but to see these, it's just awesome."

Shiflette and her husband were out on a recent day taking photos of the animals, which resemble giant, floating brown boulders in the startlingly blue thermal bath.

She described the experience of watching the manatees as "calming," their sleeping forms rising to the surface periodically to draw a breath, then sinking into the crystalline water.

Manatees are very susceptible to cold weather. They can suffer hypothermia and cold stress and will eventually die if they are in water below 68 degrees.

Cold weather and boat strikes are the cause of most manatee deaths. In 1991, there were only about 1,200 manatees in Florida waters. Now, that number has risen to 6,300, and the U.S. Fish and Wildlife Service has proposed changing their status to the less dire "threatened."

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