He says that when water temperatures dip below 68 degrees Fahrenheit , these subtropical animals simply ca n't cope with the cold . Cold has killed 5 percent of West Indies manatees spring , 280 in all . Wildlife official : Manatees ca n't cope when water is colder than around 78 degrees . Manatee are already endangered , and spring known deaths were a record 429 . Necropsy lab official says she fears more may die in 2009 from lingering effects of cold .
Cold has killed 5 percent of West Indies manatees spring , 280 in all . Wildlife official : Manatees ca n't cope when water is colder than around 78 degrees . Manatee are already endangered , and spring known deaths were a record 429 . Necropsy lab official says she fears more may die in 2009 from lingering effects of cold .