Flies like to play and have fun like other animals, according to a fascinating new study

Male fruit flies buzzing around in a small, contained arena sounds like a pretty ordinary science experiment. Yet one group of researchers noticed something unusual about how some of them reacted to a spinning disk.

They observed that while many flies stayed away from the disk, a select few hopped onto it and stayed for surprising amounts of time.

Dr. Wolf Huetteroth from the University of Leipzig notes that these findings could open new questions about how body awareness develops in living creatures.

Flies spin with purpose

Many people think of fruit flies as tiny creatures flitting around fruit bowls. Yet a recent study suggests that they might show optional behavior patterns that fit the definition of play. This observation challenges old assumptions about insects.

“Using several carousels, we generated and analyzed a total of around seven years of film data,” says Dr. Tilman Triphan, the first author of the study.

Researchers used several rotating platforms placed under a thin glass cover. Some flies dashed to the edge, but others returned to the carousel again and again. 

Individual preferences

A fraction of the flies sought the disk and rode it in repeated sessions. Those individuals spent extended periods on the spinner, while their peers avoided it altogether. The behavior looked deliberate, rather than forced or random.

One aspect was the difference in how these seekers got onto the spinning surface.

“However, we were able to distinguish whether the flies had deliberately walked onto the carousel or jumped onto it in an uncoordinated way. This allowed us to show that unplanned visits to the carousel were rather atypical for the playing flies,” says co-author Dr. Clara H. Ferreira, an assistant Professor at Northumbria University.

Possible value of body sense

The repeated interaction with the moving disk seems to involve proprioceptive feedback, which refers to the body’s sense of position and motion.

If some flies are actively seeking the extra sensation, it might be fulfilling a hidden benefit. This is reminiscent of how certain mammals, like rats, engage in rough-and-tumble routines that refine their coordination.

Some insects ended up swapping mealtime for more spins on the carousel. That trade-off hints at a possible reward gained from the turning motion.

The interesting part is that these insects showed no direct advantage other than what seems to be playful amusement.

Flies spin by choice, not force

Natural curiosity is often observed in higher animals, but insects rarely get credit for it.

Here, the setting was calm, with continuous observation over days to capture genuine conduct. There were no artificial triggers that forced the flies onto the disk.

The team set up the environment to ensure no threat forced the flies to remain. If the spinning platform caused anxiety, they could easily walk away.

Instead, some made a personal choice to return. This self-directed action adds weight to the suggestion of a real playful attitude.

Why does it matter for humans?

“This could help us to find out how we humans also develop efficient self-awareness of our bodies,” says Huetteroth.

The clue lies in how the spinning motion may sharpen the brain’s ability to map physical space. Because the flies appear to seek out extra movement, they might be training themselves to adapt and respond to unexpected motion.

Similar responses appear in many species that enjoy roller coasters or spinning rides. Researchers believe the brain learns from these experiences, reinforcing internal models of balance and orientation.

If a small insect displays a version of this, it might show that the drive to engage in such activity evolved long ago.

Flies spin despite easy alternatives

The flies had easy access to food and water. They also had corners to rest without interruption. Despite these calmer options, some crawled over for a spin.

That behavior did not enhance survival, which points toward a motivational factor besides hunger or fear.

Scientists have used open-field tests to measure caution or stress in animals.

Usually, creatures stay near edges when anxious. The carousel-seeking flies, however, went to the center and stayed. This breaks usual fear-driven patterns.

What happens next?

So far, scientists have only glimpsed how fruit flies pick between exploration, feeding, and spinning. The genetic tools available in fruit flies might shine more light on the neural wiring behind this playful bent.

Perhaps targeted genetic studies will uncover exactly which circuits reward them for spinning.

In time, deeper understanding could reveal ways that controlled motion shapes a creature’s internal map.

That concept might prove relevant to other animals, including humans learning how to handle complex movement or interactive environments.

The study is published in Current Biology.

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