Exploring Uncharted Waters: Do Fish Play (and Why Yes)?

***Written by Sofia Eisenbeiser***

Ever had this feeling that fish in your aquarium are having a blast?  This summer I am working with a few of them to determine whether or not they exhibit play behaviors.  

This study began as a simple replication of Dr. Gordon Burghardt’s 2014 publication, which found that three white-spotted African cichlid fish (Tropheus duboisi) appeared to be playing with a thermometer in their aquariums.  Not only did they play, but each one appeared to play differently, each interacting with their thermometer in their own unique ways.  (That’s where things started… but keep reading to find out where they’ve gone!)

The presence (or absence) of play behaviors in low-level vertebrates has long been a contentious issue (Burghardt, 2014), and for good reason.  Firstly, how do we define complex behaviors in creatures that we don’t understand well in the first place?  How do we separate data from anthropomorphization and subjective hopefulness enough to determine scientifically that something – say, a fish – plays?  How can we?  

Well, to begin we must first lay out a set of criteria that allows us to examine behaviors and categorize them.  Luckily, Dr. Burghardt is way ahead of us.  His five proposed criteria for play behavior are as follows:

1. The performance of the behavior seen does not appear completely functional, that is, it includes elements or is directed toward stimuli that do not contribute to immediate survival. 
2. The behavior appears to be spontaneous, voluntary, pleasurable, or in some way ‘‘done for its own sake.’’ 
3. The behavior may resemble ‘‘serious’’ performance of ethotypic behavior, but differs in being incomplete, exaggerated, awkward, precocious, or involves altered sequencing of modal action patterns.
4. The behavior is repeated during at least one developmental period in life. 
5. The behavior is most reliably initiated when the animal is not seriously stressed or under intense competing motivations.

Basically (to put it less sciencey), in order for a behavior to be entertained as play it needs to NOT serve an immediate function (like the functions served by feeding, navigation, or aggression behaviors); it is performed spontaneously and voluntarily; it may resemble certain functional behaviors but differs in context, particular movements of the body, or is ultimately incomplete (like “play fighting” in puppies – although it may resemble real fighting, certain elements of the overall behavior differ from the real thing). Finally, the behavior must be done more than once, and the animal needs to be in reasonable conditions free of stress, hunger, predation, competition, etc.  

Makes sense, right?  These criteria will likely be tweaked or expanded upon for this project, but stay tuned.

Here’s a video of one of the BYB fish chasing after a laser pointer!  Would you define this behavior as play?

So, where are we now?  As I’ve watched the behavior of my fish over time, from first getting them, to losing a few, to seeing them settle into their new home, and then eventually separating them into their own sections of their aquarium, I’ve found that their behavior overall has changed markedly throughout the few weeks I’ve had them.  

That’s why my project has turned from one solely about play to one about play AND fish behavior in general.  With the help of a couple of GoPros and a program named BORIS, I’m analyzing every single thing our fish do while keeping a close eye out for play.  The BYB team is also working on an AI software that will be able to detect fish and analyze their movements (i.e. behaviors) for us!  

Another very exciting goal for this project is to work with teachers to develop lesson plans that could be implemented easily in the classroom to allow middle and high school students the opportunity to conduct their own, in-depth scientific experiment at school.  This year, the BYB 2021 Summer Fellowship has selected a group of teachers to do just that, and I’ve had several meetings with our “teacher fellows,” who have given me some fantastic insights into what goes into formulating and implementing lesson plans at various grade levels.

Now, you might be thinking “Who cares whether fish play?” “So what?”  Well, it’s known that play is a function that is essential for the cognitive, emotional, and social development of human children (Ginsburg, 2007), but there’s very little literature that looks into the evolution of play over time, from the very beginning.  

Could it be that play is a function that has remained in our genetic code from the time we were only fish?  Perhaps play behavior itself has grown to be more advanced over time right along with us, to eventually become something vital to the development of a healthy, curious, expansive human mind.  

Meet the rest of my fish!

A Bit About Me

I’m currently a senior at Eastern Michigan University studying neuroscience and philosophy.  I have an apartment just a 15 minute walk away from the BYB headquarters where I live with my small cat named Sibyl and all of my plants (who do not have names).  When I’m not researching fish brains, you might find me reading neuroscience-related literature, rereading the classics, hiking, baking, or working on a farm outside of town.

My interest in neuroscience has been with me for just about always.  After considering cowgirl, astronaut, princess, and president, I finally landed on neuroscientist.  I’ve found it to be an absolutely enthralling field that allows me to learn about a little bit of everything, even fish!  I’m looking forward to the rest of the summer with BYB to continue my education in neuroscience and beyond.