Male bottlenose dolphins form the largest known multi-level alliance network outside humans, an international team led by researchers at the University of Bristol have shown. These cooperative relationships between groups increase male access to a contested resource.
The scientists, with colleagues from the University of Zurich and University of Massachusetts, analysed association and consortship data to model the structure of alliances between 121 adult male Indo-Pacific bottlenose dolphins at Shark Bay in Western Australia. Their findings have been published today in The Proceedings of the National Academy of Sciences (PNAS).
Male dolphins in Shark Bay form first-order alliances of two-three males to cooperatively pursue consortships with individual females. Second-order alliances of four-14 unrelated males compete with other alliances over access to female dolphins and third-order alliances occur between cooperating second-order alliances.
Co-lead author Dr Stephanie King, Associate Professor from Bristol’s School of BiologicalSciences explained: “Cooperation between allies is widespread in human societies and one of the hallmarks of our success. Our capacity to build strategic, cooperative relationships at multiple social levels, such as trade or military alliances both nationally and internationally, was once thought unique to our species.
Read more at University of Bristol
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