Male bottlenose dolphins match the tempo of each other’s calls when working together, as well as synchronising their movements, a study has found.
An international team of researchers used long-term acoustic data from the famous population of dolphins in Shark Bay, Western Australia.
The study, published in the journal Proceedings of the Royal Society B, found that male dolphins co-ordinate their behaviour in a similar way to humans when working together.
Male dolphins were shown to match the tempo of their partner’s calls and sometimes produce their calls in sync.
It was previously thought that only humans used both physical and verbal synchronised actions to strengthen bonds and improve co-operation.
Male dolphins need to work together to herd a female and defend her from rival alliances, but they are also competing to fertilise her. Such synchronous and co-ordinated behaviour between allied males may therefore promote co-operative behaviour and regulate stress, as it has been shown to do in humansDr Stephanie King
The research was carried out by an international team from the Universities of Western Australia (UWA) and Bristol.
Dr Stephanie King, senior lecturer from Bristol’s School of Biological Sciences, said: “Male dolphins need to work together to herd a female and defend her from rival alliances, but they are also competing to fertilise her.
“Such synchronous 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.”
In humans, synchronised actions can lead to increased feelings of bonding, foster co-operation and reduce the perceived threat of rivals.
Apart from humans, very few animals co-ordinate both vocal signs and physical movement when working together.
The study found that male bottlenose dolphins not only synchronise their movements but also their vocal behaviour when working in alliances.
Bronte Moore, who worked at UWA’s School of Biological Sciences, said male bottlenose dolphins “can form alliances that can last for decades”.
“To advertise their alliance relationships and maintain their social bonds, they rely on synchronous movements,” she said.
– The study was funded by The Branco Weiss Fellowship – Society in Science, and the National Geographic Society.