Male bottlenose dolphins use "names" to identify their friends and rivals, researchers says.

A study of 17 adult male bottlenose dolphins in Shark Bay, Western Australia, found they are the only animals apart from humans that give a name to members in their social circle, the researchers say.

Lead researcher Stephanie King, of the Centre of Evolutionary Biology at the University of Western Australia, said using individual names allowed male dolphins to track co-operative partners and competitors and to form strong bonds with one another.

Scientists recorded the dolphins' chatter to identify individual males, then checked to see if they all used a unique "word" call when communicating with other males about a dolphin with which they shared a relationship.

The finding is unusual as groups of animals usually make just their calls similar in their social group, as seen in some birds, elephants and primates, Dr King said.