Multiple paternity in socially monogamous prairie voles (Microtus ochrogaster)

Prairie voles (Microtus ochrogaster (Wagner, 1842)) exhibit behavioral, morphological, and neuroendocrinological traits associated with monogamy and are considered a model system to examine the biological foundations of monogamy in mammals. We examined allelic polymorphism at microsatellite loci to assess mating exclusivity in wild prairie voles sampled in east-central Illinois and found evidence of multiple paternity in five of nine litters (56%) analyzed. Thus, a female in this socially monogamous mammal with extensive mechanisms for pair bonding does not always mate solely with its partner and raises the paradox of why some pair-bonded females mate multiply.