People and manatees don’t always mix well. Humans bring pollution and development and speedboats that threaten manatee habitat or directly injure the giant, gentle sea cows. But in southern Florida, there’s also a strange, and strangely moving, symbiosis at work between the two species.adcelannotate = {"mobilepaywallcategory" : "MOBILE_PREM-TRAVEL","nativepaywallcategory" : "NATIVE_PREM-TRAVEL"};