Mice that grow up smelling cat urine will not run away when they meet cats.

The cat-and-mouse battle turned out to be a huge turning point, as a team of Russian researchers found that mice exposed to a chemical in cat urine at an early age would behave as cats approached. That’s too bad for a rat.

Cat urine contains a substance called L-felinine, which mice have learned to respond to during evolution. When rats smell L-Cat Urine, the body produces a stress hormone called adrenaline, which prompts them to escape.

When a mouse grows up smelling cat urine, it can’t run away when it meets a cat.

Female mice can smell more L-cat uric acid, which can even trigger hormonal reactions, stopping reproduction altogether or reducing litter production, the researchers said. This response is not unique to mice, and many animals suspend reproduction or delay production when they know of nearby natural enemies.

However, researchers Vera Voznessenskaya and colleagues found that if mice grew up exposed to cat urine, cats would not escape when they appeared. They presented the findings at the annual meeting of the Association for Experimental Biology in Prague earlier this week.

Within two weeks after the mice were born, the researchers exposed them to cat urine and the taste of pure L-cat urine. This period is called critical period by biologists, when young animals learn key information about their surroundings. Birds will remember who their mothers are during this period, during which time human beings learn languages faster and easier. Obviously, this is also when young mice learn to smell cats and not run away.

In addition, Voznessenskaya and colleagues fed milk to mice while they smelled cat urine, so the mice linked the smell of cat urine to food, making them less likely to escape.

In this way, these mice should be well adapted to the existence of cats, even if they know they will be eaten, it does not matter right? Absolutely wrong. The mice in the experiment had severe stress reaction when they smelled L-cat uric acid. The body secreted a lot of adrenaline. They were very afraid, but they did not run away.

It sounds a bit like Stockholm Syndrome (also known as the hostage complex), which refers to a complex in which the victim of a crime has feelings for the perpetrator, and in turn helps the perpetrator. ) But the researchers say this only shows that the body’s stress response is innate and genetically controlled, but that mice can learn different response behaviors.

Of course, this may not be common in real life, but it still makes people wonder, if cat urine can control mice, then what do cats do to us?