Fish may seem to just swim around without much thought or character. But new research reported in Ecology and Evolution has suggested that actually, fish have personality, which they exhibit in their behavior. The researchers suggested that the way a fish swims can reveal a lot about what kind of fish it is; the movement and broad patterns of behavior seen in fish indicate that they have a 'micropersonality.'
The study did not use anthropomorphic adjectives like bold, adventurous, shy, or sedentary, but showed how different fish could be described this way. In this work, the researchers tracked the movement of fifteen different three-spined stickleback fish that were swimming in various tanks that either contained two, three, or five plastic plants that stayed in the same places. Video recordings of the fish were taken and analyzed by computational tools that indicated how much time the fish spent stationary, moving, stopping and starting, and how often they turned.
The analysis showed that the fish moved in very different ways. These experiments were also highly repeatable; the researchers could identify each fish just based on its movement data from different experiments with different environments.
"These micropersonalities in fish are like signatures - different and unique to an individual. We found the fish's signatures were the same when we made simple changes to the fish tanks, such as adding additional plants," said study co-author Dr. Ines Fürtbauer of Swansea University.
"However, it is possible these signatures change gradually over an animal's lifetime, or abruptly if an animal encounters something new or unexpected in its environment. Tracking animals' motion over longer periods and in the wild will give us this sort of insight and help us better understand not only personality but also how flexible an animal's behavior is," added Fürtbauer.
Additional work will be needed with other species to see whether this is a more generalized feature of animals, and whether similar patterns exist in species that dwell on land or that fly.
"Our work suggests that simple movement parameters can be viewed as micropersonality traits that give rise to extensive consistent individual differences in behaviors," said lead study author Dr. Andrew King of Swansea University. "This is significant because it suggests we might be able to quantify personality differences in wild animals as long as we can get fine-scale information on how they are moving, and these types of data are becoming more common with advances in animal tracking technologies."