Dolphins are the largest social network after humans

Shannon BaileyAugust 30, 2022

Dolphins are the largest social network of social cooperation after humans, a characteristic that has been considered unique to our species: these animals form alliances at several levels that give males greater access to females, thereby increasing their reproductive success. This discovery comes from a group of researchers led by the American University of Massachusetts at Dartmouth and the British University of Bristol, which published The results are in the Journal of the US National Academy of Sciences (PNAS). The study highlights that dolphin communities, as well as those of non-human primates, are valuable models for understanding human social and cognitive development as well.

A group of four males allied to share a female (Source: Simon Allen)

The researchers, led by Richard Connor of Dartmouth University and Stephanie King of the University of Bristol, studied alliances within a group of 121 male dolphins (Tursiops truncatus) living in Shark Bay, Western Australia. These samples form first-level cooperative networks, consisting of two to three males, to share access to a female. These primary cores then form an alliance in the larger second level groups (consisting of 4 to 14 samples) and finally the third level.

Intergroup cooperation in humans was thought to be unique and based on two other characteristics that distinguished us from our common ancestor with chimpanzees: the development of marital bonds and parental care by males. “However, our results show that alliances between groups can emerge even without these characteristics,” comments Connor, “of a social and mating system more similar to that of chimpanzees.”

A group of four males allied to share a female (Source: Simon Allen)