 Crystal River National Wildlife Refuge in Florida is home to a myriad of species, but there's one in particular for which it's known. The West Indian manatee. Manatees inhabit these shelter waters year round, and Crystal River Refuge was created specifically for their protection. But manatees float right beneath the surface, making them very hard to see, especially from a moving boat. And deep cuts from low propellers are one of their biggest threats.