Fish Just Want to Have Fun: Study

Fish just want to have fun, according to a University of Tennessee, Knoxville, study that finds even fish "play."

When we think of animals that like to play, dogs, kittens, even otters come to mind. But according to Gordon Burghardt, a professor in the university's departments of Psychology and Ecology are Evolutionary Biology, the idea of "play" can also be applied to species not previously thought to be fun-loving - such as wasps, reptiles and invertebrates.

"Play is repeated behavior that is incompletely functional in the context or at the age in which it is performed and is initiated voluntarily when the animal or person is in a relaxed or low-stress setting," Burghardt explained in a statement.

Out of the hundreds of species of cichlid fish, one species in particular seems to want in on the fun.

The research team studied and filmed three male fish individually over the course of two years. During that time, the cichlids found a certain bottom-weighted thermometer amusing, repeatedly hitting it just for fun. The presence or absence of food, or other fish within the aquarium or visible in an adjacent aquarium, had no effect on their behavior.

"The quick righting response seemed the primary stimulus factor that maintained the behavior," Burghardt said. "We have observed octopus doing this with balls by pulling them underwater and watching them pop back up again. This reactive feature is common in toys used for children and companion animals."

Just like any animal's biology or cognitive abilities, "play is an integral part of life," according to Burghardt. Equal to emotions, motivations, perceptions and intellect, it is part of a species' evolutionary history and is not just random, meaningless behavior.

Burghardt believes that by more accurately characterizing play and observing it throughout the entire animal kingdom, humans may even be able to better understand themselves.

The findings were published in the journal Ethology.