As social species, the social networks of lizards, hyenas, and dolphins influence every pivotal aspect of their lives: finding a mate, reproducing, getting sick, or surviving.
In the journal Nature Communications, two biologists from the University of Pennsylvania report a mathematical model of the way social networks arise in animal populations. Their model considers the likelihood that a newborn forms connections with its mother’s connections or other individuals not connected to its mother, with the assumption that an individual is more likely to connect with those connected with its mother.
Though relatively simple, their model generated networks that faithfully recapitulated important properties of networks observed in field-collected data from four very different animal populations: spotted hyenas, sleepy lizards, rock hyrax, and bottlenose dolphins.
“What we show,” says coauthor Erol Akçay, an assistant professor in the biology department, “is that we can fit this simple model to real-life networks and capture their degree distribution, or how connected everyone is, and, more strikingly, we can also capture the distribution of what’s known as the clustering coefficient, which measures how cliquish the population is.”
How Do Social Structures Emerge?
For as long as biologists have been studying animal populations, they’ve made observations about social relationships in the group. But it has only been in the last decade or so that social-network analysis has come to the fore in generating an understanding of the dynamics of these networks.
“There has been an explosion of studies in the last 10 years or more,” says coauthor and postdoctoral researcher Amiyaal Ilany, “showing that social networks have implications for longevity or disease transmission or reproductive success. It’s become quite clear that social network structure is important.”
