Collecting the skin left behind by whales when diving provides a non-instrusive way of studying them.
Watch Blue Planet Live: https://www.bbc.co.uk/programmes/p0722ql7
Animal Slow Motion: http://bit.ly/EarthUnpluggedSlowMotionTimelapse
Big Questions with Maddie Moate: http://bit.ly/BigQuestionsWithMaddieMoate
Wilderness Sessions: http://bit.ly/WildernessSessionsFilms
Welcome to Earth Unplugged! We make films about the incredible natural world, we investigate the conundrums, quirks and beautiful science of our amazing planet, delving into the BBC vaults and mixing it up with our own stuff to take a brand new look at Earth.
Want to share your views with the team behind BBC Earth and win prizes? Join our fan panel here: http://tinyurl.com/YouTube-BBCEarth-FanPanel
This is a channel from BBC Studios who help fund new BBC programmes.Service information and feedback: http://bbcworldwide.com/vod-feedback--contact-details.aspx