According to a new study, bumblebees don’t just work hard—they like to play too. Scientists observed that the little insects enjoy rolling small wooden balls for no apparent reason other than for pleasure.

“As humans, we might believe that we are the smartest and perhaps the only creatures in the animal queendom capable of having feelings and subjective experience, but is this true?” posits  Samadi Galpayage, a Ph.D. student at Queen Mary University of London, and the study’s primary author.

The emotional states of a bumblebee

Recent data reveals that bees can experience both pleasant and negative emotion-like states. Typically, bees are given food rewards in studies to measure their abilities. In this new experiment, bees were given tiny balls and received no reward while they engaged with them, hopping on top of them and pushing them around.

“The behavior was voluntary and spontaneous,” Galpayage explains. “Bees have a reputation of being hard workers, which they are, but the prospect of bees engaging in something like play is certainly novel and exciting because it shows that bees may experience pleasure and don’t only carry out duties that are strictly essential for immediate survival, such as foraging.”

Earlier studies involved training bumblebees to roll balls toward a target in exchange for a yummy treat. The researchers observed that bees would occasionally roll the balls outside of the experiment even though they weren’t getting rewarded for it.

“This observation gave rise to new questions: What are they doing? Why? Is this random or repeated? Which bees do this?” says Galpayage. “Since there was no incentive to roll these balls, as bees were not getting any food for doing so, the observation provided a testable hypothesis of whether this phenomenon was something like play.”

Work hard play hard

For this recent study, the researchers conducted a number of experiments. In one of them, they observed 45 bumblebees in an enclosed arena where they could either proceed down a clear path to a feeding area or deviate into areas with wooden balls.

It turns out that the bumblebees would go out of their way to interact with the balls. Each participant rolled the balls between one and 117 times during the experiment. According to the researchers, the fact that they performed it repeatedly with no food payoff implies that the process was satisfying in its own right.

In another experiment, 42 bees could enter two colored chambers, one containing balls and one without. When given the option of choosing between two chambers without balls, the bees chose the chamber that was the same color as the prior one that included balls.

Rolling balls did not provide them with food, clear debris, or aid in mating in any of the studies. Moving the balls served no purpose other than to have fun.

Defining “play”

To define the ball rolling as “play,” the scientists measured the action against a framework with five criteria.  This included the notion that the behavior did not contribute to survival strategies, began in a stress-free environment, and was intrinsically pleasant.

“Mainly, we found that bees engaged in the ball rolling activity repeatedly despite the absence of an external incentive, such as getting food/mates/shelter. Rather, the behavior was rewarding in itself, which is what play is,” Galpayage says.

They also discovered that bee play patterns changed with age, which parallels those of other young mammals. Younger bees were more involved with the balls than older bees, and males rolled balls for longer lengths of time than females.

“That bees may play is an important finding for science because it provides further evidence that an insect may experience something like pleasure,” says Galpayage. “Personally, I find this behavior fascinating because it tells us that bees, like many other animals, are more than little robotic beings, but have a richer behavior and life than we would have previously thought.”

Source study: Animal Behaviour— Do bumble bees play?