Monogamy in primates and humans is the result of the need to prevent infanticide by unrelated males according to researchers from University College London, the University of Manchester, the University of Oxford and the University of Auckland

“This is the first time that the theories for the evolution of monogamy have been systematically tested, conclusively showing that infanticide is the driver of monogamy. This brings to a close the long running debate about the origin of monogamy in primates.” according to the researchers. Previously the rise of monogamy in primates and humans was thought to have come from the additional benefit of paternal care when the cost of raising offspring is high like it is in primates due to their large brains and slow development, the need to guard solitary females from rival males, and infanticide risk from rival males. The researchers gathered data from 230 primate species. A family tree of the relationships between the primate species was developed. Bayesian methods were used to determine when each potential behavior that produced monogamy evolved and what behavior evolved first. Monogamy won out in humans and their ancestors because the development of primates is slow and the need for protection from an infanticide that would allow the female to be sexually receptive to a rival male was a predominant factor in human’s evolutionary past.