A team of researchers and a team of rats recently got together for some laboratory-based hijinks. They spent weeks playing human-vs-rodent hide-and-seek, which was so much fun the impish little rats literally giggled and jumped for joy.

The diminutive players consisted of six adolescent male rats who were trained to play hide-and-seek against neuroscientist Annika Stefanie Reinhold. The researchers filled a room with hiding places made from different boxes and allowed the rats to become accustomed to the space. The critters learned that if they began the game inside a closed box, they were the seeker, while being in an open box meant they needed to hide. The findings are reported in Science.

Over time, the rats became stealthier, working out that opaque boxes make the best hiding places and checking spots where their two-legged rival had hidden before when seeking. When learning to play the game, the rats were rewarded for success through tickles, strokes, and a bit of rough-and-tumble play.

"They chase our hand, we tickle them from the side, it's like a back and forth a little bit like how you play with small kittens or puppies," Humboldt University’s Konstantin Hartmann told AFP.

As well as playing for these interactions, the rats were motivated by the fun of the game. They would jump for joy and even let out high-pitched “giggles”, suggesting they were in high spirits. If you’re wondering why you’ve never heard a rat laugh, their mischievous giggles have to be picked up by scientific equipment as they’re too high-pitched to be detected by the human ear.

Another sign that the rats were enjoying themselves was that they would often leap away to hide in a new location once they’d been rumbled. Like excitable children, they wanted to keep playing again and again.

While the fact that delighted rats have been scurrying around playing hide-and-seek for weeks is definitely the news we all need right now, you might be wondering why busy scientists thought it was a good use of their time.

The team recorded nerve signals coming from the prefrontal cortex of the rats’ brains, an area involved in learning. They assessed which neurons were firing at different points in the game, for example, a third sent out signals when the rat learned whether it would be hider or seeker.

While research like this can tell us more about learning in the mammalian brain, it can also help us better understand the importance of play. Future studies could look into the effects that not being allowed playtime might have on the brain, revealing how children and teenagers denied the opportunity to have fun and play with others might be affected.

"This type of research will also help other scientists to see in rats more than what you usually see when you just get the rat and use it for standard experiments, when you're not aware of what these animals can do," Hartmann told AFP.

"When you work a lot with rats over the years, you see how intelligent these animals are and how social. But it was still very surprising to us to see how well they did.”