Overview: In this Inside Nature's Giants Special, the BAFTA-winning team battle through the night against a rising tide to explore the mysteries of the largest predator on Earth: the sperm whale. Veterinary scientist Mark Evans and comparative anatomist Joy Reidenberg dissect the whale's enormous organs to reveal the secrets of this 45-foot deep-sea giant, which stranded and died on Pegwell Bay in Kent in March this year. Despite their enormous size, we know very little about sperm whales because their lives are normally hidden deep beneath the waves. The programme reveals how they can survive diving down thousands of metres for over an hour on one gulp of air in conditions that would freeze our blood and crush our bones.