While filming orcas, Steve Backshall witnessed them hunting and killing prey, but not for food. He explains why they do this and how he’s processed this disturbing behaviour. Subscribe: http://bit.ly/BBCEarthSub #BBCEarth #BadNatured Watch more: Planet Earth http://bit.ly/PlanetEarthPlaylist Blue Planet http://bit.ly/BluePlanetPlaylist Planet Earth II http://bit.ly/PlanetEarthIIPlaylist Planet Dinosaur https://bit.ly/PlanetDinosaurPlaylist Welcome to BBC EARTH! The world is an amazing place full of stories, beauty and natural wonder. Here you'll find 50 years worth of entertaining and thought-provoking natural history content. Dramatic, rare, and exclusive, nature doesn't get more exciting than this. Want to share your views with the team? Join our BBC Studios Voice: https://www.bbcstudiosvoice.com/register This is a commercial page from BBC Studios. Service information and feedback: http://bbcworldwide.com/vod-feedback--contact-details.aspx