Throughout the animal kingdom, individuals have been found to behave consistently different from one another over time or across different contexts. This is now mostly referred to as “animal personality”. As part of my PhD I want to understand what role such personality traits play in the structuring and functioning of social groups, i.e. in collective behaviour.

Today I am running an experiment to investigate the consistency of risk-taking behaviour, also known as the boldness personality trait. I work with three-spined sticklebacks that I caught in wild streams near Cambridge. The three-spined stickleback is a wonderful little fish that is not only easy to work with and keep in the lab but a model system for collective behaviour and animal personality.

Topview of the boldness tank with left the deep covered area that leads to an increasingly shallow area on the other side. You can see a fish and its trajectory in the toplane

In their wild habitat these fish often hide under plant cover but sometimes go out of cover to search for food or join group mates. However, out in the open they are easier prey to predators such as the pike and heron. Therefore, an ecologically relevant way to test their risk-taking is by exposing them to a tank that contains cover, as well as an increasingly shallow open and thus potentially more risky area.

I test fish individually for one hour per day in this risk-taking tank and test them on multiple occasions, ideally multiple days apart so really show fish are consistent in their risk-taking behaviour. It always is remarkable to see the large variability between fish and their consistency over time. Some fish simply barely go out of cover, while others go out and explore the increasingly shallow side of the tank and do so repeatedly.