Male Mice Afraid of Protective Mothers and Bananas, Here's Why

McGill University experts discovered a compound that triggers mice to repel dangers from their offspring. This chemical is prevalent in mothers and is responsible for the sensitivity experienced by the male animals when exposed to female mice under gestation and lactating phase.

This compound enhances the stress hormones of male mice and increases their tolerance to pain when a factor in proximity to pregnant females.

Why Aggressive Male Mice Turn from Pregnant and Lactating Counterparts

Male Mice are Afraid of Protective Mothers and Bananas, Here’s Why

(Photo: Aleksandar Pasaric from Pexels)

McGill's Department of Psychology and Alan Edwards Centre for Research on Pain specialist Jeffrey Mogil, who served as leader of the study, explained that their findings add to the essential aspects commonly considered when carrying out scientific examinations involving mice subjects.

The research contributes to the unknown factors in a laboratory setup that influences the outcomes of mice-related studies, Mogil continued.

McGill University fellow and co-author Sara Rosen said that the experiment they processed demonstrates how the female mice signal male individuals that are likely to attack their babies. Rosen explains that these mothers tend to protect their offspring vigorously, adding that the stress the team observed is possibly due to the threat of an upcoming fight between the female and male mice.

Contrary to what we know, mice have a better ability to communicate with each other, and this feature relies heavily on their sense of smell, Mogil said.

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The olfactory chemicals in mice were the main interest of the study. These compounds keep an organism's responses and stress-related behaviors up and running. In the study, one particular chemical was discovered to induce the communication skills of the mice.

This odorant, known as n-pentyl acetate, is released from the urine of pregnant and lactating mice. It could also activate whenever a gestating female is stressed towards the presence of male mice.

Banana Scares Male Mice, Too

Olfactory systems in animals regulate how the species detect and translate airborne molecules we know as odors. For humans, these molecules serve as attributes for themselves, the food they eat, the identities of animals and plants, and other aspects scattered across the environment.

According to the NIH National Center for Biotechnology Information, information from olfactory chemicals could drive how an organism carries out its feeding behaviors, reproduction, and even social interactions.

Co-author Lisa Lima said that the olfactory signal n-pentyl acetate could also be identified in the unique smell stimuli of the banana fruit. In the experiments the team conducted, the smell of banana extract from the supermarket was discovered to stress male mice as much as how females react when they protect their babies.

Mogil concludes that this information can be considered a breakthrough in the science behind the social signaling of mammalian species. Although there is already olfactory signaling between male and female rodents specified in previous studies, only a few samples show how male-to-female signaling works when taken outside the aspects of sexual behavior, Mogil added.

The study was published in Science Advances, titled "Olfactory exposure to late-pregnant and lactating mice causes stress-induced analgesia in male mice."