Humans have long wondered if the universe may harbour other intelligent life forms. But perhaps we need look no further than our oceans?

Whales and dolphins, like humans, have large brains, are quick to learn new behaviours and use a wide range of sounds to communicate with others in their society. But how close are their minds to ours? In the Bahamas, Professor Denise Herzing believes she is very close to an answer, theorising that she will be able to hold a conversation with wild dolphins in their own language within five years.

In Western Australia, dolphins rely on their versatile and inventive brains to survive in a marine desert. In Alaska, humpback whales gather into alliances in which individuals pool their specialised talents to increase their hunting success. We discover how young spotted dolphins learn their individual names and the social etiquette of their pod, and how being curious about new objects leads Caribbean bottlenose dolphins to self-awareness and even to self-obsession. Finally, the film shows a remarkable group of Mexican grey whales, who seem able to empathize with humans and may even have a concept of forgiveness. Show less