You may not be able to play a proper game of fetch with fish, but that doesn't mean they don't know how to have fun. It turns out that some species of fish play to have fun just like other animals, according to a new study published in the journal Ethology. This is the first study that shows that cichlids, a species of freshwater tropical fish, play with objects.
A research team that included University of Tennessee professor Gordon Burghardt, psychology research assistant Vladimir Dinets and James Murphy of the Smithsonian National Zoological Park, observed, studied and filmed three male fish during a period of two years. The fish repeatedly attacked a thermometer in a tank, which satisfied Burghardt's definition of play.
"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 said in a statement.
Burghardt's definition of play has also allowed researchers to find evidence of play among species previously thought not to participate in the activity. This includes wasps, reptiles and invertebrates.
The behavior of the fish was a "quick righting response," according to Burghardt, which many other types of animals show, from octopus to pets to children. In fact, Burghardt said this research can actually help humans better understand themselves. This and his past research shows the psychology of play and how it is a part of species' evolutionary history.
Apparently, male cichlids are pretty rambunctious creatures. When they're not playing, they fight, which I suppose could also look like playing, and they do so by determining the size of each other's mouths. National Geographic has a video of it, and it's pretty sick.
For animals, some play has little to no function. However, play can be used for exercise, for survival in the case of play fighting or be crucial for the animal's growth and development. Research by Sergio Pellis has found that when rats aren't able to play fight as pups, they don't develop social skills to interact with other rats, don't get the know-how to recognize and escape from danger and don't learn how to properly engage in sexual behavior since play fighting often mimics that.
We all know what happens when it's all work and no play, but Burghardt probably said it best. "Play is an integral part of life and may make a life worth living."
