Programme website: http://www.bbc.co.uk/programmes/b04b6982 Using a hydrophone, Lucy Cooke discovers that Dolphins use names to get each others attention.
Dolphins Give Each Other Unique Names
Dolphins: Deep Thinkers (Objects have names)
Dolphins May Call Each Other by Name
Dolphin Cruise | LEGO Friends | Full Episode
Nova Science Now : How Smart Are Dolphins?