The "Second Life" of laboratory rats ( Rattus norvegicus ): Assessment of social behavior of a colony of rats based on social network analysis.

Rattus norvegicus is a social animal and holds a significant economic value, considering its use in scientific research. Here, we use the Social Network Analysis (SNA) approach to study the social interactions of a group of rats held in a post-laboratory animal care facility. We collected interaction data during four study periods, for a total of 60 days. At the group level, rats presented two communities for each study period, consisting mainly of littermates. At individual level, we found that the rats preferred to interact with individuals of the same strain and laboratory of origin and with littermates. At temporal level, we studied how stable social interactions were over time. During the first study period, we found high social stability, whereas the introduction of new individuals in the subsequent period caused social rearrangements; however, the initial social stability was restored. Our findings have shown that studying the social behavior of rats using SNA is a valuable tool for advancing our understanding of the social system of this species, which has the potential to enhance management and welfare practices.