The complex social life of rats uncovered with potential implications for human psychiatry

The biological properties of rats show much greater similarities to human cells and organs than most people would expect. In simplified terms,

nearly 90% of the genes in humans and rats share significant similarities.

The researchers at ELTE observed varied patterns of dominance and coexistence, challenging preconceived notions about rats and potentially human social interactions. In some instances, hierarchies stabilized only after numerous conflicts, while peaceful cohabitation was the norm in other scenarios. These dynamics were influenced significantly by the composition and reorganization of the rat groups, showcasing the profound impact of the social environment on behavior.

When rats from a hierarchical group were mixed with those from a non-hierarchical group, the outcome was sometimes a hierarchical group, and sometimes a peaceful one. Another unexpected result was that there was relatively little correlation between the "personality" traits defined in standard personality and social tests (commonly used in drug or behavioral research) and the actual behavior observed within the real groups.

This suggests that rats' social lives, socialization, and relationship to their traits are far more complex than can be interpreted using any simple mechanism. One interesting aspect of this result is that when examining the effects of certain psychotropic drugs in animal experiments,

researchers must be extremely cautious with their conclusions, as rat group behavior contains paradoxes.

The rats were color-coded so that the automated system could track them 24 hours a day for eight months.

The Department of Biological Physics at ELTE, in collaboration with Enikő Kubinyi at the Department of Ethology, conducted this important, gap-filling research and published it in „Scientific Reports”, part of the „Nature” portfolio. The research began as part of an ERC Advanced Grant previously awarded to Tamás Vicsek, professor emeritus at the Institute of Physics, but processing the vast dataset generated took years.

The resulting publication is a unique work in its field, due to the enormous amount of data behind it, the design of the experiments, and the wide range of evaluation methods used. Máté Nagy played a key role in the design and execution, while Gábor Vásárhelyi developed highly innovative software solutions for processing the visual data.

At the end of the experiment, the researchers made efforts to take care of the animals, and they were delighted that all of them found adoptive homes.

A series of recordings from the experiment can be viewed in the following video (showing a week's worth of the four colonies' nights in fast-forward, as the rats are mostly inactive during the day, sleeping or huddling together) Credit: The Department of Biological Physics at ELTE   

Publication details: M. Nagy, J.D. Davidson, G. Vásárhelyi, D. Ábel, E. Kubinyi, A. El Hady & T. Vicsek (2024) Long-term tracking of social structure in groups of rats. *Scientific Reports*, (2024) 14:22857, https://www.nature.com/articles/s41598-024-72437-5

Photo credit: The Department of Biological Physics at ELTE