The prairie voles are always touted as paragons of monogamy, ever since Sue Carter at the University of Illinois made headlines by "turning off" pair bonds in females by blocking the effects of oxytocin.
The idea is that in the brains of monogamous animals, including humans, oxytocin and dopamine interact in the brain's reward centers to create what's sometimes described as an addiction to the mate.
But Carter and her early collaborator, Larry Young of Emory University, constantly reiterate that the voles are socially monogamous. In other words, they live in stable families consisting of a mating pair -- that stays mated for life -- and virgin offspring. This doesn't stop them from extra-pair copulation.
I went to a seminar last year in which Young said that a very high percentage of male prairie voles never become monogamous.
Now, new research published in Nature showed that the prairie voles cheat a lot. Lead researcher Alexander Ophir quantified these extra-pair couplings, but found that it didn't have any effect on the vole couples' ability to successfully breed and raise offspring.