Individual differences drive social hierarchies in male mouse societies

Social hierarchies play a crucial role in organizing groups of animals, granting advantages to those at the top. In mice, hierarchy positions can either emerge from the group's composition at a specific moment or be stable traits ingrained within individuals. Dominance and submission are demonstrated through actions like competing for tubes or chasing each other. However, the complex ways in which these behaviors influence social standing within larger groups of male mice remain largely unexplored.

To shed light on this issue, researchers created the NoSeMaze, a semi-naturalistic, open-source, modular setup that allows for automated, long-term monitoring of undisturbed mouse groups. Over the course of more than 4000 mouse-days, the hierarchies formed through spontaneous tube competitions proved to be non-despotic, transitive, and stable even when the makeup of the groups changed.

This stability suggests a deep-rooted internal component to competition-based social rank. Chasing behavior, too, remained consistent across different situations. Interestingly, the majority of chasing was observed among high-ranking individuals, indicating an ongoing negotiation of social rank among the top players.

The connection between chasing and social rank grew stronger in groups with less defined rank structures, where mice tended to rely more on aggressive signals to establish their position. Chasing behavior, social rank, and specific physical and cognitive traits were found to be associated with each other. Overall, employing the NoSeMaze to track mice in high-dimensional settings revealed that social position is multifaceted and shaped by stable individual behaviors that persist despite shifts in social contexts.

This method enables researchers to model individuality and social position as crucial resilience factors in mouse societies.