Dolphins plug coral hideouts with sponges to trap fish, Sir David Attenborough's Blue Planet III reveals

For 40 years, marine biologists believed Shark Bay's bottlenose dolphins carried sea sponges to shield their snouts or attract mates. Cameras off Western Australia caught one, named Gambara after an Aboriginal word for clever, wedging a sponge into a coral 'bommie' before scaring fish into the sealed hideout. Director Yoland Bosiger thinks Gambara is around 40. Only a select few dolphins have mastered the skill, passed from mother to calf.

Attenborough calls it 'one of the most sophisticated examples of trap-setting in the animal kingdom'.

Bosiger says Attenborough rewrote 'every single line' of her opening episode.

The six-part series took four years to film and airs during Attenborough's centenary year.