Monogamous relationships among certain primates can help reproduction, promote peaceful living and lead to better care of infants, new research finds.
The study, published in PLoS ONE, focused on intense relationships that occur among nocturnal owl monkeys, but close couples also form in titi monkey, gibbon, marmoset, tamarin monkey and, of course, human populations.
The important factor is not just monogamy, but "pair bonding."
"By pair bonding we mean a strong, enduring and relatively exclusive relationship," lead author Eduardo Fernandez-Duque told Discovery News, adding that such bonding is also associated with reproduction. The relationship "may last forever, or it may be relatively long, but not forever."
Fernandez-Duque, an associate professor in the University of Pennsylvania's Department of Anthropology, and co-author Maren Huck amassed data from 16 years of observing 18 owl monkey groups - 154 animals living in a portion of Argentina's Chaco region.
The researchers closely observed monkey pairs and documented their relationship dynamics along with reproductive rates. They found that owl monkeys with one partner produced 25 percent more offspring per decade than those with two or more partners.
"What we're showing is that if you manage to stay with the same partner, you produce more infants than if you're forced to change partners," Fernandez-Duque said.
It's not yet clear why this happens, but one theory is that the two individuals - as with most human couples - take time to assess one another before reproducing. Owl monkey fathers, like good human dads, "are immensely committed to providing care for their infants," he said. Moms of this species are also very devoted to their offspring.