MANATEES

Resembling land mammals as much as any sea creature, the manatee is a gentle giant vegetarian. The world's largest population of manatee is in Florida, but even there, fewer than 3,000 individuals are in existence. Why they're in trouble: In addition to passing problems like the 2010 winter freeze that harmed manatees and other sea creatures in Florida, toxic algae (caused by human pollution), loss of habitat and boating collisions.