A new study published in the journal Proceedings of the National Academy of Sciences has revealed that, for female mongooses, the cost of deadly war is worth it so long as it helps you find a mate. The research found that female banded mongooses will purposefully lead their groups into frays so that they can mate with enemy males while the chaos rages on. The anarchic mating strategy is thought to preserve genetic diversity as female mongooses will rarely leave the family group into which they’re born, meaning they need to get inventive if they want to avoid inbreeding.
The researchers from the University of Exeter and the University of Cambridge, both in the UK, were studying banded mongooses in Uganda and wanted to investigate the motivations behind fighting between groups. Mongooses are known for their violent fights and it's often the males that bear the brunt of the trauma, being the most likely to sustain injuries or even die in a fight.
There are different models of leadership within social groups, and when it comes to waging war these can be heroic or exploitative. Heroic models see the initiators of fights contributing the most to the battle, while exploitative models see initiators sending others into harm’s way while they do little themselves to help.
The researchers used long-term data from wild banded mongooses to test which model was being employed by these animals and found that cross-group fights were mostly being started by females. They found these individuals were starting conflicts as a means of increasing reproduction opportunities, as warring with enemy groups gave them access to unrelated males. The exploitative strategy meant the related males were busy fighting while the frisky females scoped out the competition for worthy suitors.
While it might sound a little savage to sacrifice the safety of your family in the pursuit of procreation, the behavioral adaptation is a necessary one. “Mongooses have family-based groups where older siblings, aunts and uncles all play a role within the group and the raising of offspring,” said ZSL London Zoo keeper Tara Humphrey in an email to IFLScience. “Their groups are more female populated, with only related males who are forced out when they reach sexual maturity.” As such, if females are to avoid inbreeding, they need to find a strong healthy male outside of the family, and where better to judge the survival skills of a partner than in the throes of battle.
"We've known for some time that banded mongoose groups often engage in violent battles and now we know why," said Professor Michael Cant, from the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall, in an email statement. "Females start fights between groups to gain genetic benefits from mating with outsiders, while the males within their group, and the group as a whole pay the costs.
"A classic explanation for warfare in human societies is leadership by exploitative individuals who reap the benefits of conflict while avoiding the costs. In this study, we show that leadership of this kind can also explain the evolution of severe collective violence in certain animal societies."