Doludda, B.; Bogado Lopes, J.; Zocher, S.; Kempermann, G.; Overall, R. W.

Early social interactions critically shape lifelong individual behaviour but their development and stability have been difficult to study in laboratory settings. Our experimental platform allows the automated real-time and longitudinal study of social structure in mice living in a shared environment, providing previously inaccessible behavioural measures. These include estimates of directed agonistic activity for the reconstruction of social hierarchies and their dynamics over the life-course. In an all-female colony of genetically identical mice, pairwise inter-individual interactions revealed stable dominance hierarchies that already emerged early in life. Older animals introduced into a new colony exhibited a steeper hierarchy compared to adolescent mice or mature mice that had been co-housed throughout life. Our longitudinal analysis of social dominance hierarchies highlights the critical role of early-life experience.