Spotted hyenas, just like Facebook users, tend to form bonds with friends of friends, a phenomenon known to behavioural scientists as “triadic closure.”
“Cohesive clusters can facilitate efficient cooperation and hence maximise fitness, and so our study shows that hyenas exploit this advantage. Interestingly, clustering is something done in human societies, from hunter-gatherers to Facebook users,” explains lead author Amiyaal Ilany, a postdoctoral fellow at the University of Pennsylvania.
Hyenas, which can live up to 22 years, typically live in large, stable groups known as clans, which can comprise more than 100 individuals.
They are socially sophisticated animals, which can discriminate maternal and paternal kin from unrelated hyenas.
But they are discerning in their social choices and prefer to bond with the friends of their friends, the study found.
The animals follow complex social rules, although those governing males are more rigid. Females tend to change their bonding preferences. This is probably because females stay for life within the clan they are born, while males leave for a new clan at puberty, where they start at the bottom of the pecking order.
Ilany and his colleagues collected more than 55,000 observations of social interactions of spotted hyenas over 20 years. The ability of individuals to form and maintain social bonds in triads was key to the animals’ social cohesion.
Knowing why and how these animals form relationships can help scientists better understand cooperation patterns and the consequences of sociality in other species. The research was published in Ecology Letters.