We’ve all spent long lazy afternoons answering questions that could help identify our personality type. Popular social media sites are filled with quizzes and questionnaires that help you figure out why you are the way you are.

We have engaged in long-standing debates about if animals have personalities and if we can really understand their behavior and communicate with them. This is especially true with creatures that call oceans their home. A myth about how fish cannot feel pain and how lobsters and shrimp too, cannot experience hurt due to the lack of a central nervous system. Though this has never been proven, they are still cooked alive in most parts of the world. 

But what if we told you that you can gauge a fish’s personality just from the way it swims? This finding, by a team of researchers from Swansea University and the University of Essex proves that you can gauge a fish’s personality by observing how they swim. 

This new research published in Ecology and Evolution details the methods used to reliably measure animal personality simply from the way individual animals move. Known as a micropersonality trait, observable in humans too include small mannerisms and physical traits that set us apart. Like you can distinguish between a friend and a stranger based on their gait and movement alone, the researchers have studied the movements to fish to gather crucial data. 

Study Methods:

The team of biologists and mathematicians used high resolution video footage of three-spined stickleback fish (Gasterosteus aculeatus) in a tank to gauge their movement patterns over time. Using plastic plants placed at strategic locations within the tank, the team members were able to gather an assortment of data including speed, directional changes, trajectory and acceleration.

Using this data, the team were able to track the everyday movement of these fish and found some highly repeated patterns. Each fish had its own unique ‘movement signature’ meaning that each individual in the tank displayed a repeatable and distinct moving pattern which the researchers could use to differentiate between the fish without even looking at them.

The team were able to easily define a fish based on its individual movement parameters and ‘repeatable interindividual differences’ in how they moved around the tank. By placing two, three or five plants, the team could accurately study individuals that were more active in the tank and moved around a lot, took long winding routes exploring their habitat or fish that moved in fast hurts and remained almost still at other times. 

This subsequently allowed the researchers to determine if a particular individual was more keen on exploration with a confident air of ownership of space or if an individual was more timid and spent time secluded to a safe corner of the tank with rare exploratory swims. 

Behavioral parameters in fish are defined by their freedom to explore open waters, ability to rise above the protection of rocks and crevices and head into higher areas within the tank or the curiosity they display in exploring substrate, looking for food and finding mates etc. Using their movement patterns, the team of researchers were able to determine the behavior of individual fish and distinguish between individuals. 

The team used the two approaches—quantifying movement and behavioral parameters. By extrapolating from the movement data gathered from video analysis, the team derived interindividual differences in behaviors between individual fish. Defined as  “micropersonality” traits, these movement differences help understand the personality too.

“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 Dr Ines Fürtbauer, a co-author of the study from 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 behaviour is,” she added. 

Significance of Findings

Using hi tech cameras, the team were able to record intricate data like the fish’s turn angle, step length, burst frequency, total distance per exploration and total distance travelled. This allowed the team to learn about patterns and gauge how each fish operated. Much like how a human’s daily schedule tells you a lot about them as people, the fish’s routine was very illuminating too. 

The team were able to collect all available data and use it to plot graphs that showed the average movement patterns of all fish and how they ranked individually for each of these parameters. For example, one of the fish showed remarkably high step length compared to the other fish, meaning it maintained its burst of speed for longer and traveled further distance – showing a confident and energetic personality.

“Our work suggests that simple movement parameters can be viewed as micropersonality traits that give rise to extensive consistent individual differences in behaviours,” said Dr. Andrew King, lead author from Swansea University. According to him, this adds to existing knowledge about data collection regarding animal behavior. This method can be used to study other wild animals too, provided such intricate data is available. 

For larger land dwellers, microtagging and GPS data could also help derive crucial movement parameters that can then be used to gather significant information about how the species thinks, reacts and behaves. This could prove crucial to conservation efforts too, because understanding an animal helps greatly in preparation and education of a conservation program. 

But, applying this across all species might be tricky as a lot of data is required and researchers need to analyze how general this phenomenon is and if moment parameters can help establish the personality traits of individual animals. Each species is different and requires unique methods of research. But the findings of this paper could apply to other fish, helping us gauge the intricate lives they lead, the personalities they display and how they interact with the world around them.