Asha de Vos: Why you should care about whale poo

Whales have a surprising and important job, says marine biologist Asha de Vos: these massive creatures are ecosystem engineers, keeping the oceans healthy and stable by ... well, by pooping, for a start. Learn from de Vos, a TED Fellow, about the undervalued work that whales do to help maintain the stability and health of our seas — and our planet.