A joint team of researchers from the United States, Australia and the University of Zurich’s Anthropological Institute & Museum built on studies from the 1990s which found that two to three males would form an alliance to steal females from a group for mating purposes.
Interested in the way that these renegade dolphins formed their teams, researchers looked at the structure of these male relationships.
They found that dolphins have exceedingly complex bonds with one another, and that their relationships are not based on an obvious group structure. In this way, they are comparable only with humans.
The dolphins’ behaviour was also likened to that of chimpanzees, which are also known to forge alliances.
But whereas chimps develop alliances to defend territories from attack by members of the same species, the dolphins were bonding to defend their females.
It was previously thought that male dolphins would only come together for the mating season, but the study has shown that this is not in fact the case.
“Our study shows for the first time that the social structure and associated behavior of dolphins is unique in the animal kingdom,” University of Zurich’s Michael Krützen said in a statement.