Close encounters with killer whales
Andreas B Heide is a marine biologist and conservationist from Norway who's devoted the past three years of his life studying killer whales - also known as orcas. But he doesn't just study them from a boat - he straps on a wetsuit and dives into the cold water to swim with them. He tells Manuela Saragosa what it's like hanging out in the water with one of the most dangerous marine predators in the world. You can find out more about his research at www.barba.no.
Image: Andreas B Heide diving with a killer whale