Male dolphins work together just the same way as humans

Marine scientists have found that when it comes to working together, male dolphins co-ordinate their behaviour just like us.

The finding is important, the authors of a new report say, because it provides insight into the importance of physical and vocal co-ordination in alliance-forming animals.

In humans, synchronised actions can lead to increased feelings of bonding, foster co-operation and diminish the perceived threat of rivals.

It was previously thought only humans co-ordinated both verbal signals and physical movement when working together.

The study, by a team from the University of WA and the University of Bristol, used long-term acoustic data collected from the population of dolphins in Shark Bay, north of Geraldton in Western Australia.

It showed that allied male dolphins also matched the tempo of their partner's calls when working together, and would sometimes even produce their calls in sync.

Lead author Bronte Moore, who carried out the study while working at UWA's School of Biological Sciences, said allied male bottlenose dolphins were also well known for synchronising their physical behaviour and could form alliances that lasted for decades.

"To advertise their alliance relationships and maintain their social bonds, they rely on synchronous movements. We wanted to know whether they would also synchronise their vocal behaviour," she said.

"The study showed that male bottlenose dolphins not only synchronise their movements, but also co-ordinate their vocal behaviour when cooperating together in alliances.

"This behaviour may help reduce tension between the males in a situation that requires them to cooperate successfully."

Former UWA researcher Stephanie King, now at the University of Bristol's School of Biological Sciences, said male dolphins needed to work together to herd a female and defend her from rival alliances, but were also competing to fertilise her.

"Such synchronised and co-ordinated behaviour between allied males may therefore promote co-operative behaviour and regulate stress, as it has been shown to do in humans," Dr King said.

The study is published in Proceedings of the Royal Society B.