Sperm whales are the largest predators in the world. But even something so large can have enemies... Subscribe: bit.ly/BBCEarthSub #BBCEarth #OceanGiants Watch more: Planet Earth bit.ly/PlanetEarthPlaylist Blue Planet bit.ly/BluePlanetPlaylist Planet Earth II bit.ly/PlanetEarthIIPlaylist Planet Dinosaur bit.ly/PlanetDinosaurPlaylist Ocean Giants, 2011 Dolphins and whales may appear to be totally alien to us. But with their mental ability, group communication and the discovery that dolphins have individual names, they are closer to us than we ever imagined. Ace underwater cameramen Doug Allan and Didier Noirot embark on a quest to film the most amazing stories of whales and dolphins across the ocean world. They uncover new insights into the lives of these extraordinary animals that will redefine how we see them forever. Welcome to BBC EARTH! The world is an amazing place full of stories, beauty and natural wonder. Here you'll find 50 years...