WASHINGTON (CBSDC/AP) — Only a few species of mammals are monogamous, and now two scientific teams think they’ve figured out why they got that way. But their answers aren’t exactly romantic.
One team looked just at primates, the animal group that includes apes and monkeys. The researchers said the exclusive pairing of a male and a female evolved as a way to let fathers defend their young against being killed by other males.
The other scientific team got a different answer after examining about 2,000 species of mammals. They concluded that monogamy arose in mammals because when females were spread out geographically, males had trouble guarding them against competitors unless they stuck close by.
British and Australian researchers compared results from 230 primate species over the course of 75 million years, and they found that the threat of infanticide — specifically, the threat of baby primates being killed by unrelated males — likely triggered monogamous behavior.
Infants’ are dependent on their mothers throughout childhood, and since female primates typically delay further conception while they are nurturing their young, male competitors may see advantages in doing away with babies that their rivals have sired, study lead author Christopher Opie, a postdoctoral research fellow in the department of anthropology at the University College London in the United Kingdom, told Live Science.
The studies are published online Monday in the journals Science and the Proceedings of the National Academy of Sciences.
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