Banana chemicals caused a stressful response in male mice (Image: Getty)
Researchers have made a strange discovery about male mice: bananas stress them out.
The discovery was made unintentionally while scientists were studying the reaction of male mice to pregnant and lactating females.
Over the course of the study, the researchers observed that the chemical compounds in bananas triggered a stressful response in male mice.
‘Male mice show stress and induced stress [pain inhibition] in the vicinity of pregnant or lactating female mice, “said the study, published in Science Advances.
The McGill University of Montreal team also found that pregnant and lactating female mice responded to unknown male mice with “aggressiveness and urine marking.”
The discovery was made unintentionally while scientists were studying the reaction of male mice to pregnant and lactating females (Image: Unsplash)
Male mice are known to be aggressive and infanticide with puppies. Therefore, very pregnant and lactating female mice emit chemicals to warn these males.
“Rodents and many non-human mammals depend on their sense of smell,” the study’s lead author, Professor Jeffrey Mogil, told Live Science.
“Urine odor marking is well known, but what we found here is a new message that has never been described before in mammals.”
Although olfactory messages are usually sent from males to females, there are fewer examples of females sending them to males.
In this case, the researchers believe that the females are “telling the males to stay away.”
This is where bananas come in.
The authors found that the compound n-pentyl acetate, which is found in the urine of female mice during subsequent pregnancy and lactation, is similar to a compound found in a variety of fruits and used to produce banana extract.
Male mice are known to be aggressive and infanticide with puppies (Image: Shutterstock)
This is the chemical that caused extreme hormonal changes in male mice.
Thus, when the team bought banana oil extract from the supermarket and placed it inside the cages of male mice, their stress levels increased significantly.
The stress response in mice was found to be similar to the stress response when it was about to fight.
The significance of this finding is that even in the absence of an aggressive female, the mere threat of this aggression, communicated through banana compost, is sufficient to stress male mice.
The study found that virgin male mice were more likely to be stressed by the presence of n-pentyl acetate, either in bananas or in mouse urine.
This fits with their tendency to be more aggressive with babies than non-virgin mice, suggesting that they are more of a threat to babies than older males.
MORE: A virgin mouse gave birth to a litter of mice
MORE: The Omicron variant could have mutated from mice, the study says