Male bottlenose dolphins have their own individual "names," which they use to communicate with each other and build a social circle, an Australian study has found.

The male bottlenose dolphin develops a "signature whistle" or identity signal within the first few months of its life that is structurally unique, according to the study released Friday in the journal Current Biology.

"[The] signature whistle is a rare example of a non-human mammal using a learned vocal label that can be considered somewhat comparable to a human name," the study said.

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"Bottlenose dolphins are adept vocal production learners, a notably rare skill in mammals, and use vocal learning to develop their individually specific signature whistle, which they use to broadcast their identity," it continued.

"We found that individual male dolphins retain their unique signature whistle, allowing them to recognize many different friends and rivals in their social network, something not currently known from any other non-human animal," said report co-author Stephanie King of the University of Western Australia wrote at The Conversation.

"It has been shown that these signature whistles are somewhat comparable to human names. Dolphins use them to introduce themselves or even copy others as a means of addressing specific individuals," King continued.

Shared identity signals

The study also revealed that, as in humans, where it has been found that people's speech can become similar if they are close, male bottlenose dolphins also experience phonetic convergence.

"Convergence onto shared or similar identity signals has been documented in allied male bottlenose dolphins," the study said.

Convergent vocal accommodation is used to signal social proximity to a partner or social group in many species.

As for the motives behind these "alliance signatures," the study said suggested benefits included "broadcasting alliance identity as a specific social unit toward other allied males or to sexually receptive females."