Manatees are among nature's strangest-looking, gentlest animals. They're among America's most endangered mammals and were the basis for ancient tales of mermaids, legendary creatures that were half-fish and half-human.
M. Timothy O'Keefe has been a diver for more than 30 years. He is an award-winning author and his articles and photographs have also appeared in numerous publications worldwide, including National Geographic Society books, Time-Life Books, Newsweek, and more.