Becky and Emily voyage into the big blue with 28,000 bath toys, a pod of talking sperm whales and a floating log.

They hear from the episode producer John Ruthven who talks about the challenge of finding your subject to film in the wide open ocean. He unlocks the code that whales use to communicate and translates their click patterns.

Sir David tells us about his hopes for the future of conservation and a Blue Planet II Podcast exclusive: what animal he would like to be reincarnated as.