Now, Steven Phelps from the University of Texas at Austin has shown how these differences in behaviour are connected to differences in the voles’ genes. Specifically, males can inherit variants of a particular gene that affect a part of the brain involved in remembering places. If they have variants that confer poorer spatial memory, they are worse at remembering the locations of social encounters, more likely to wander out of their own territories, more likely to meet other females, and more likely to have pups out of volelock.

Scientists have been studying the social lives of prairie voles since 1971, when Lowell Getz first discovered their long-term bonds. Together with neurobiologist Sue Carter, he showed that these bonds depends on