Blue Planet II

Synopsis

In recent years, our knowledge of life beneath the waves has been transformed.

Using cutting-edge technology, One Ocean takes us on a journey from the intense heat of the tropics to our planet's frozen poles to reveal new worlds and extraordinary never-before-seen animal behaviours.Starting in the tropical coral reefs - the most diverse ocean habitat - a baby dolphin is taught the secrets of a coral reef, as its family rubs against a particular gorgonian which may have medicinal properties.

On another reef, a tusk fish demonstrates a surprising level of ingenuity - tool use - as it uses corals as an anvil to break open clams. In the Seychelles, half a million terns nest on an island. Fledglings must eventually take to the wing, but danger lurks beneath the waves - metre-long giant trevally fish leap clear out of the water to snatch the birds.