Manatees on ice

When the polar vortex brought freezing temperatures to Florida earlier this month, the state's manatee population had to figure out how to survive. Despite their "sea cow" nickname and appearance, manatees don't have a lot of insulating fat on their bodies. If the water temperature dips below 68 degrees F for very long, they can get sick and die.

The solution: Manatees gather together in water that maintains its temperature year round, like this naturally hot pool at Florida's Blue Springs. The record for greatest number of huddled manatees is 567, according to the Tampa Bay Times. Besides natural springs, they also like the outflow from power plants. A coal-fired plant like the Big Bend Power Station near Tampa Bay uses quite a bit of water — coal is burned to heat water that turns into steam, which turns the electric turbines. The steam then cools a bit and turns back into water and is discharged from the power plant, still warm from its journey. The discharge makes a perfect environment for chilly manatees.

Image: Manatees, a Creative Commons Attribution Share-Alike (2.0) image from bohemianism's photostream