We recently wrote that cats are not inferior in mind to dogs. It turns out that now representatives of the feline family can note the outstanding abilities of rats - according to the latest research, laboratory rats can learn to play hide and seek and even enjoy it. The unconventional experiment, published in a recent issue of the journal Science, sheds light on the tiny rodents' sophisticated sense of play and the complex mechanisms at work in their brains. The researchers also concluded that this type of game is not without evolutionary benefits.
Games are an important part of mammalian evolution
In recent decades, scientists have begun to explore the neural, behavioral, and evolutionary foundations of play. The point is that games can be confusing because they lack an obvious purpose. However, all kinds of animals from rats to elephants and humans love to play. According to experts, in a sense, games are an important part of mammalian development. Games probably help train the brain. This opinion is shared by a neuroscientist at the Humboldt University in Berlin, Michael Brecht, the lead author of the study.
In the study, scientists have documented simple play patterns in all mammalian species, including laboratory rats, which have been found to emit ultrasonic "giggles" when tickled. Can you imagine? Unsurprisingly, Brecht and his colleagues have listened to rat owners saying their pets can learn to play hide and seek. The uniqueness of the experiment lies in the fact that hide and seek is a rather difficult game for several reasons. It requires an understanding of the rules, as well as a clear understanding of the individual roles of the players and the ability to take on different roles in different rounds.
How scientists played hide and seek with rats
The researchers taught six male rats to play hide and seek one on one. They equipped a large room with cardboard barriers and small containers that served as a refuge for both rats and humans. The game began when the rat was placed in a small box in the middle of the room. If the rat had to search, the scientist would hide and then remotely open the box. And if the rat had to hide, the scientist crouched at the box when the rat came out, prompting the little rodent to hurry to the shelter. All six rats learned to look for scientists, and five of them were able to hide.
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Typically, in experiments with laboratory rats, researchers reward the rodents with food. But Brecht and his colleagues knew that rats could be trained to perform very difficult tasks by offering more than food as a reward, so they wanted to achieve a natural reaction to the game. Thus, during a game of hide and seek, when a scientist found a rat, or when a rat found a scientist, the animal was rewarded with affection, tickling, or a playful fight before the game continued.
The rats were surprisingly sophisticated players. If scientists let them spy, the rats used visual cues to find scientists faster. The animals also checked the hiding places that their opponent had used repeatedly. When the person was found, the rats emitted ultrasonic signals that the scientists measured but did not hear. Experts suggest that the signals may resemble the triumph of the winner and mean "I found you!"
However, the strategies of the rats' behavior changed completely when they were to be sought. They changed their hiding places frequently and preferred to hide in opaque boxes instead of transparent ones. When found, the rats made no sounds, indicating that they were trying their best to stay undetected. At the same time, a sign that the rats enjoyed the game, scientists consider the fact that the rodents often actually prolonged the game, running away from researchers and hiding, thereby delaying social interaction. There were other signs that the rats were enjoying hide and seek, Brecht said. They often "jumped up and down happily," teased the scientists, and made a lot of noises as the game ended and began.
How does the rat brain respond to the game of hide and seek?
While the rats played, the researchers monitored the brain activity of individual neurons in the medial prefrontal cortex, an area associated with rule compliance and social closeness. Scientists found that rat neurons responded specifically to various events in play.
The fact that the rats learned the rules so quickly and were able to play with such sophistication means that the concept of the game is not new to the rats, Brecht said. This behavior is probably widespread in the animal kingdom, although exactly how many animal species indulge in games is still unknown. Experts who did not take part in the study note that the very fact that the rats enjoyed playing is surprising. According to the lead author of the study, it is possible that games help young individuals learn to hide from predators, as well as establish social interaction with other individuals.
