Physicists are also interested in fish -- above all when they are researching the formation of structures. A research team from Heinrich Heine University Düsseldorf (HHU) and the University of Bristol (United Kingdom) has examined the schooling behaviour of zebra danio (Danio rerio, also known as "zebrafish") using methods from the field of multi-particle physics. In the scientific journal Nature Communications, they explain that groups of just three fish already move in a similar way to large schools while, by contrast, two fish display completely different behaviour.

Physicists have now investigated how various large groups of living creatures behave. They wanted to know the minimum group size needed for the movement patterns of the individual members to change and become a coordinated group movement. And three does indeed seem to be the key number for zebrafish.

Looking to the future, the researchers are aiming to apply their findings to the group behaviour of people and how they behave for example at parties or mass gatherings. Löwen: "We will see whether the simple limit of the number three then also applies."