A new study from the University of Bristol has revealed that male dolphins can recognize cooperative members of their group. The researchers discovered that male dolphins develop a social concept of team membership based on the cooperative investment of other individuals.
“Humans use accrued social knowledge to classify individuals into meaningful groups, which can encompass sporting teams, social castes and political alliances,” wrote the study authors.
“Indeed, the maintenance of cooperation in human societies depends, in part, on our ability to classify relationships according to their cooperative payoffs. While many animals are capable of distinguishing between in-group and out-group based on simple rules of familiarity or spatial location, others are also capable of classifying individuals who live in the same group using accumulated social information.”
“In social birds and mammals, for example, individuals interact in stable and predictable ways, allowing them to be classified into groups according to matrilineal kinship or linear rank order. Some primate species are even able to classify individuals hierarchically, by both kinship and rank.”
In collaboration with experts at the University of Zurich and University of Massachusetts, the team analyzed 30 years of observational data from a dolphin population in Shark Bay, Western Australia.
The researchers also conducted experiments to investigate how male dolphins responded to the calls of other males from their alliance network.
“We flew drones above dolphin groups, recording their behavior during the sound playbacks, tracking their movements underwater and revealing novel insights into how dolphins respond to the calls of other males in their network of allies,” explained Dr. Simon Allen.
Males showed a strong response to allies that had consistently helped them out in the past, even if they were not close friends. On the other hand, the dolphins did not respond to individuals who had not consistently helped them out in the past, even if they were friends. This means that the dolphins have a concept of team membership and can categorize allies based on past interactions.
“Social animals can possess sophisticated ways of classifying relationships with members of the same species,” said Dr. Stephanie King. “In our own society, we use social knowledge to classify individuals into meaningful groups, like sports teams and political allies. Bottlenose dolphins form the most complex alliances outside humans, and we wanted to know how they classify these relationships.”
“Such concepts develop through experience and likely played a role in the cooperative behavior of early humans. Our results show that cooperation-based concepts are not unique to humans, but also occur in other animal societies with extensive cooperation between non-kin.”
The study is published in the journal Nature Communications.
By Chrissy Sexton, Earth.com Staff Writer