The researchers found that mating relationships co-evolved with several behaviours. “When the mating system changed, the behaviour changed,” says Opie. But of all the behaviours, infanticide by rival males was the only one to consistently precede a shift to monogamous mating, they report today in Proceedings of the National Academy of Sciences1. The fear of infanticide alone can be postulated as a cause of monogamy in primates, Opie says; the other behaviours are consequences.
Lukas and Clutton-Brock also ran the analysis on primates only, but unlike Opie and his colleagues, they found no association with infanticide. Clutton-Brock says that the discrepancy could be a result of different ways of categorizing the behaviours. “We clearly must get together with Opie to sort this out,” he says.
Could be an idea.
Opie calls the Cambridge study “interesting and ambitious” and says that his results for primates must be a peculiar subset. He says that his ultimate interest is in probing the origins of human monogamy. “It’s hard work in my experience, so why would so many primates do it?” he asks.
In the case of humans, maybe Someone told them to. 😉
“We’re very cautious about extending our conclusions to humans,” says Clutton-Brock. “Humans are so very unusual because they have culture — and that changes things.”
Well, humans have a sense of the future. That is, we can see that if we do not form long term relationships ( = where people need us far more than we need them), we won’t have them around when we need them but they don’t need us. Last I heard, it was called longevity. Married people live longer.