David Attenborough examines the methods of communication in the animal kingdom. The love song of a fish keeps the inhabitants around San Francisco Bay awake, the river banks in Malaysia teem with millions of tiny beetles and the world's loudest birds scream through the rainforest.

David Attenborough looks at the many and varied ways that animals ensure their genes are passed on to the next generation.

Creatures will go to any lengths in order to make babies - to continue the line by passing on genes is the ultimate triumph.