Why are male rats so scared of bananas?

Researchers from McGill University in Montreal, Quebec, discovered their unusual distaste for the fruit while analyzing stress hormones that spiked in male rats when they were close to their offspring. pregnant or lactating females. This is due to a compound called n-pentyl acetate in the urine of female rats. It is also the compound that gives bananas its distinctive flavor.

Exposure to the compound n-pentyl acetate causes stress in male rats.

Jeffrey Mogil, study author and professor in the department of psychology at McGill University said: 'This whole finding was a surprise because we didn't actively learn about it but discovered it by accident. out. Pregnant female rats were in our lab for another experiment and one of the students noticed that the males started acting strange.'

In the paper, the researchers wrote: "Male rats, especially virgin males, often act indiscriminately aggressive to enhance their heritability." To deter these dangerous predators, pregnant and lactating female rats emit a chemical reaction through their bodies, to send a message to males to stay away from their offspring.

'Rodents and many other mammals in addition depend on the sense of smell,' said Mogil. And rats also communicate with each other through their sense of smell. We've seen a lot of olfactory messages being sent from males to females, but rarely the reverse. Most of these messages are related to sexual behavior, but in this case, sex has nothing to do with it. This is a warning message from children to stay away from their children, or there will be an intense fight."

Levels of stress-induced analgesia were significantly higher in virgin male rats.

After observing that stress levels in males increase in response to chemicals in the female's urine, Mogil and his team wondered if n-pentyl acetate from another source would cause the reaction. similar or not. They bought banana oil from a local supermarket and added the liquid to cotton balls, then placed it in a male rat's cage. The presence of this scent also increased the stress levels of males, and researchers suspect that this hormonal increase is directly related to the stress a person feels when faced with a fight. war can happen.

In addition, exposure to urine or banana oil also reduced pain and decreased sensitivity of male rats to pain.

The study authors also found that stress-induced pain relief was significantly higher in virgin male rats, suggesting that unrelated males pose a greater threat to survival. survival of the pups compared with the fathers.

Mogil says the discovery represents a breakthrough in the science of mammalian social signaling.

'Mammalian species communicate with each other more abundantly than we initially thought,' he said.