A new study from the University of Cambridge shows that social monogamy may have evolved as a mating strategy, rather than a need for assistance with parental care as was previously believed.

In the comparative study, researchers Dieter Lukas and Tim Clutton-Brock reveal that in all ancestral groups of mammals, females lived in separate ranges while males defended overlapping territories. Monogamy evolved when males were unable to monopolize and defend multiple females, leading one breeding female and one breeding male to become closely associated over several breeding seasons.