Biologists have found that male dolphins form the largest unions for access to females

Researchers from the Universities of Bristol, Zurich and Massachusetts have found that male bottlenose dolphins form numerous branched networks that can only be compared in size to human ones. The results of the work are published in The Proceedings of the National Academy of Sciences.

The authors analyzed association data between 121 adult male Indo-Pacific bottlenose dolphins living off the coast of Australia. It turned out that two or three males form an “elite” group of the first order. They jointly maintain relationships with several females. Second-order groups consist of 4-14 males, while third-order groups arise between cooperating second-order alliances. How well these beta males negotiate among themselves depends on their reproductive success. That is, social connections lead to long-term success.

Intergroup cooperation in humans was thought to be unique and possible because of two features that distinguish humans from our common ancestors with chimpanzees: complex social bonds and male parental care. The results of scientists showed that intergroup alliances can occur without these features.