Male mice use female mice to distract attackers and avoid conflict, study finds

A research group led by Joshua Neunuebel from the University of Delaware, US, tracked the behavior of mice using machine learning to understand how they deal with the aggressive behavior of other mice. The researchers’ conclusions, published October 15 in the open access journal Biology PLOSshow that male mice defuse aggressive encounters by lunging toward a female mouse to distract the aggressive male mouse.

The researchers recorded groups of two male and female mice interacting for five hours. Like many other animals, mice have social hierarchies, and in almost every group recorded, one male was always significantly more aggressive toward the other.

Social interactions can be difficult to study objectively, so the researchers used a machine learning approach to analyze aggressive interactions and how mice responded. In total, they observed more than 3,000 altercations between the male mice, and the machine learning algorithm helped the researchers determine the most likely responses to aggression and whether those actions resolved or escalated the conflict.

The researchers found that the male mouse that was encountered aggressively often lunged toward one of the female mice, which dampened the aggression. This may be a bait-and-switch tactic, as the aggressive male mouse typically followed the other male but then interacted with the female mouse instead of continuing the aggressive encounter.

Some other tactics, even if they avoided aggression for a while, then escalated into full-on fighting. However, researchers found that this was not the case after the bait and switch. After using this tactic, fighting rarely occurred, with the male mice often staying further apart from each other, with the aggressive mouse continuing to interact with the female mouse.

Although bait and switch can be an effective way to deescalate conflicts, it may have costs for the victim, such as sacrificing time with female mice, and further research could determine whether these tactics are effective in larger groups of mice.

This study also demonstrates how machine learning tools can be useful for understanding animal behavior, and similar tools could be used to study how many other species with social hierarchies handle aggression.

The authors add: “Using artificial intelligence, we discovered that male mice turn to nearby females to distract aggressors and defuse conflicts. After an aggressive encounter, the attacked male briefly engages with a female before quickly escaping, as the attacker’s attention shifts to her.”