Banded mongooses — which live in south-central Africa and look like a combination of a raccoon and a meerkat – are known for their violent intergroup battles. These conflicts are common. As many as three occur per month, often leading to injury, and sometimes death. But for a long time, scientists didn’t know why these little mammals were so prone to warfare.

A recent study analyzed 16 years of observational data to find out. Researchers found that males were more likely to shoulder the costs of battle — males made up almost all of the deaths in from intergroup fights. Females, on the other hand, almost never died in these skirmishes. While managing to avoid the negative effects of conflict, females did reap the rewards: the more conflicts her group engaged in, the more offspring she had whose fathers were not part of her own group. Since members of mongoose groups are often closely related, if the father belongs to a different group, the offspring are less inbred and more likely to survive.

Male mongooses practice mate-guarding: after mating with a female, they follow her around to make sure she doesn’t mate with anyone else. The authors suggest that because of this mate-guarding practice, the females will actually instigate fights so that, in the mayhem of battle, they can mate with the other groups’ males. While this practice is costly for the males, it’s an evolutionary advantage for females because it results in healthier offspring.