Individual Attributes Generate Contrasting Degrees of Sociality in Voles

Different species of voles (Microtus) live in different mating systems, with prairie and pine voles generally more social and more monogamous than montane and meadow voles. Mating systems are treated as epiphenomena, driven by the actions and adaptations of individual animals. The species differ with respect to morphology, development, male ejaculate capacity, copulatory behavior, parental behavior, and social contact-proneness. Natural selection appears to have acted on suites of traits of individuals and thereby produced contrasting mating systems in the field.