Male Mice Attract Mates with Tears

Male Mice Attract Mates with Tears

For men, crying may not be considered very masculine. But when a male mouse sheds tears, it seems to signal its masculinity.

Japanese researchers have discovered that male mice release pheromones in the fluid that moistens their eyes.

“No one expected sexual chemicals to be found in tears,” said Kazushige Touhara from the University of Tokyo in Chiba. Pheromones – chemicals that convey messages ranging from fear to sexual desire – are typically found in human sweat and mouse urine.

It’s unclear if mice cry for the same reasons as humans. In this study, their tears were simply a physiological response to keep their eyes moist and comfortable.

Touhara explained that the pheromones in these secretions might be detected by females when they nuzzle the faces of males. These “sexy” cues help females choose potential mates.

In most vertebrates, pheromones activate nerve cells in the vomeronasal organ, located between the nose and mouth. Touhara’s team plans to study how various pheromones affect this organ, which influences mating behavior. Initially, they searched for pheromones in mouse urine but found nothing significant. To their surprise, they discovered the critical chemical in mouse tears after examining other natural secretions.

According to the researchers, humans do not release pheromones in tears. The pheromone found in mouse tears is produced by a gene that humans do not possess.

Touhara added that the findings highlight the mystery of human tears: scientists still don’t fully understand why we cry when we’re in pain. “I think crying holds more significance than we realize,” he said.