Overview: Life defines our planet, but until recently its ability to flourish has remained a mystery. New scientific discoveries can now reveal the improbable connections, bizarre behavioural strategies and intricate mechanisms that make life on Earth possible. Discover why the Brazil nut tree depends on a sharp-toothed rodent for its existence. Find out why elephants are crucial to keeping the East African grasslands in shape. And why an intricate relationship between hawksbill turtles and sponges is vital to the health of the coral reef. Using high-end and cutting edge filming techniques, How Life Works discovers the secrets of our most crucial habitats and reveals why they are so special.