Cross-species Analyses of Social Hierarchies

Social hierarchies are found across animal taxa. We are interested in how universal social processes within social hierarchies are, and what types of variation exist in social hierarchies. Recent projects have included examining how different species establish social hierarchies. Working with Dr Ivan Chase, Stony Brook University, we have shown that groups of mice, cichlid fish and chickens show remarkable similarity in the structural evolution of networks of social hierarchies. Specifically, in each species dominant individuals tend to lay down their social dominance relationships and more subordinate individuals fill in their relationships around these. Further, we have demonstrated that social groups at the network level are extremely hierarchically organized and stable but at the triadic and dyadic levels there is much more flexibility in relationship structure.

It has been over 100 years since Thorleif Schjelderup-Ebbe published his seminal paper: “Beiträge zur Sozialpsychologie des Haushuhns“ (Zeitschrift für Psychologie 88, 1922, 225-252). This was the first study to describe in detail pecking-orders (‘Hackliste’) in chickens. Since then, social hierarchies have been studied across animal taxa. In a recent study, we have curated over 430 datasets from over 130 species including invertebrates, birds, reptiles, fish and mammals. These datasets include edgelists and sociomatrices of competitive dominance data. Our goal with this project is to provide a resource to other researchers who may be interested in cross-species analyses of social dominance. We have created an R package DomArchive that is a living repository of these data. The package also contains a vignette that describes how to use the raw social data and associated metadata.