Bottlenose dolphins tail walk backward (Photo Credit: Stewart Holmes CC by 2.0 via Flickr)

When it comes to brain power, bottlenose dolphins are second only to humans. The highly social animals are known to teach one another to tail walk, to help fellow dolphins in distress, and to even carefully prepare their food instead of instantly devouring it like most animals. Now, a new study indicates that male bottlenose dolphins maintain unique whistles, or ‘names,’ to enable them to recognize friends and rivals within their social group.

Previous research has shown that like many other creatures, including parrots, bats, elephants, and primates, dolphins develop an individual vocal call, or a signature whistle, within the first few months of their lives. However, animals form long-term alliances with other members of their species, they usually converge on a shared whistle to demonstrate their solidarity.

To investigate if the same was true for male bottlenose dolphins, who are known to form close alliances, marine biologist Stephanie King and her team recorded the signature whistles of 17 adult males, which made up six smaller groups within three larger dolphin communities in Western Australia’s Shark Bay. They then measured the similarity of these identifying signals, both within the dolphins’ most intimate group of friends and their larger networks. The analysis showed that even after developing strong bonds with other members, each dolphin retained a unique signature whistle that distinguished him from his mates. Related dolphins — those belonging to the same family — also maintained their own ‘names.’

Male bottlenose dolphins form strong alliances (Photo Credit

In the report published in the journal Current Biology on June 7, King stated, “Male bottlenose dolphins that form long-term cooperative partnerships or alliances with one another retain individual vocal labels, or ‘names,’ which allows them to recognize many different friends and rivals in their social network. Our work shows that these ‘names’ help males keep track of their many different relationships: who are their friends, who are their friend’s friends, and who are their competitors.” The University of Western Australia professor believes that “retaining individual ‘names’ is more important than sharing calls for male dolphins, allowing them to keep track of or maintain a fascinating social network of cooperative relationships.”

However, this does not mean the Shark Bay dolphins don’t demonstrate love for their friends. In lieu of adopting a similar group call, these male dolphins express their bromance with tactics like synchronized swimming or by caressing, or slapping, each other, similar to how humans display affection.

The team next plans to investigate dolphin male alliances more closely to find out if some relationships are given more importance than others. One of the tests will be to play the recorded ‘names’ of the individual males to others and observe how each member responds to them in various settings. “It will be interesting to reveal whether all cooperative relationships within alliances are equal or not," said King. We wonder if female dolphins also have unique ‘names’ to recognize each other.