Killer whale researchers (c) Victoria Gill
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The four-decade whale watchers

A team from the Center for Whale Research in Washington State has been tracking the lives of killer whales off America's North Pacific coast since 1976.

Their orca family tree is revealing new findings about the social lives of the species, and the researchers showed the BBC how they managed to track every killer whale in the most studied population on Earth.

Video by Victoria Gill and David Cheeseman

  • 10 Aug 2016