The Evolution of Monogamy ; Practice May Sound Sweet, but It Isn't Based on Romance
Seth Borenstein /, The Buffalo News (Buffalo, NY)
: Practice may sound sweet, but it isn't based on romance
Only a few species of mammals are monogamous, and now dueling scientific teams think they've figured out why they got that way. But their answers aren't exactly romantic.
The answers aren't even the same.
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 non-human mammals. They concluded that mammals became monogamous because females had spread out geographically, and so males had to stick close by to fend off the competition.
So it's not about romance, said researcher Dieter Lukas of the University of Cambridge, lead author of the mammals study. "It's just really the best he can do."
The differing conclusions apparently arose because the two teams used different methods and sample sizes, the researchers said.
But both teams discounted a long-standing explanation for monogamy, that it provides two parents rather than one for rearing offspring. That's just a side benefit, they said.
"Romance obviously came after" monogamy, said Christopher "Kit" Opie, an anthropology researcher at the University College London, who was the lead author of the primate study.
The studies were published online last month in the journals Science and the Proceedings of the National Academy of Sciences. The mammal paper in Science excluded humans, while the primate analysis in PNAS counted people both as monogamous and not, because that differs around the world.
Researchers said they hesitated to apply their conclusions to humans, and they acknowledged that their results aren't exactly the stuff of Valentine's Day.
Less than 9 percent of mammal species pair up socially.
Among primates, about 25 percent of the species are socially monogamous, Opie said. …