Genetics. In voles, a little extra DNA makes for faithful mates.
Pennisi
Elizabeth
E
D000818:Animals; D003411:Arvicolinae / Q000235:genetics* / Q000502:physiology / Q000523:psychology; D001522:Behavior, Animal; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D018895:Microsatellite Repeats; D010152:Pair Bond; D010332:Paternal Behavior; D017483:Receptors, Vasopressin / Q000235:genetics* / Q000378:metabolism; D012919:Social Behavior
D017483:Receptors, Vasopressin