Male mice are terrified of bananas. Here's why.

The distinctive scent of a banana stresses male mice out, according to scientists.

Researchers from the University of Montreal discovered this unusual fruit aversion while analyzing stress hormones in male mice when they were close to pregnant or lactating females. The scientists reported in a new study that the males and females had different levels of testosterone in their urine. It is the compound that gives bananas their distinctive smell.

Jeffrey Mogil, the study's senior author and a professor in the department of psychology, said that the whole thing came as a surprise since they were not looking for this in particular.

Male mice, especially virgin males, are well known to engage in infanticidal aggression to advance their genetic fitness, as a way to keep these potential predators at bay.

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Rodents and a lot of mammals other than humans rely on their olfactory senses. We have seen a lot of olfactory messages being sent from males to females, but there are fewer examples of females sending them to males. Sex has nothing to do with these messages at all. The females are telling the males to stay away, otherwise be prepared for me to beat the crap out of you if you touch my pups.

Mogil and his team wondered if n-pentyl acetate from a different source would cause the same stress levels in males. They put banana oil into cotton balls and placed them inside cages of male mice. The researchers suspect that the stress levels of the males were increased by the presence of the scent, just like the urine had done in prior experiments.

The study authors reported that urine and banana oil had an effect on the male's sensitivity to pain. The researchers found that the pain resistance in the male mice developed as quickly as five minutes after smelling n-pentyl acetate, and abated 60 minutes later.

The authors of the study found that stress levels were higher in virgin male mice, suggesting that unrelated males were bigger threats to the pups than the fathers were. Mogil told Live Science that the findings offer a glimpse into the invisible communication channels animals use to talk to each other.

He said thatMammals are signaling messages to one another more than they thought.

The findings were published in a journal.

It was originally published on Live Science.