In the wild (as it often is IRL), social networks play a huge part in various aspects of life, from eating to reproducing. The pups of dominant spotted hyena females, for example, get to feast on the kill before low-ranking females and all of the males. Researchers trying to understand how social networks arise have developed a mathematical model that matches up remarkably well with real-life animal networks, including that of spotted hyenas. It’s described in Nature Communications this week.
First, University of Pennsylvania’s Amiyaal Ilany and Erol Akçay modeled hypothetical social networks under the assumption that newborns could either inherit the connections of their mother or form ties randomly with individuals their mother has no connections with. In simulations where there’s a high degree of social inheritance, the baby’s place in the network and its number of contacts were all correlated with that of its mother.
Then, the team tested their model against real-world social networks: Africa’s spotted hyenas (Crocuta crocuta, pictured below), rodent-looking elephant relatives called rock hyraxes (Procavia capensis, pictured above), bottlenose dolphins (Tursiops spp.), and sleepy lizards (Tiliqua rugosa) of Australia. When their model included high social inheritance, the simulated networks faithfully matched the data on these real social systems.
Previous attempts to model the formation of social networks weren’t able to replicate the nuances of their structure – such as the number of group member interactions and the formation of cliques. “We can fit this simple model to real-life networks and capture their degree distribution, or how connected everyone is,” Akçay said in a statement. “And, more strikingly, we can also capture the distribution of what's known as the clustering coefficient, which measures how cliquish the population is."
Social inheritance, their findings show, is a key driver of structure in wild populations. Although, how social networks are passed on vary a lot between species. Some young animals have to be specially groomed by the mom during a specific window of time, some copy their mom, and still others develop relationships with their mom’s connections just being around them.
Spotted hyenas in Maasai Mara, Kenya. Amiyaal Ilany