the prairie vole compared to the montane vole which would explain why the prairie vole forms pair bonds and the montane vole does not. As noted above, different species of voles vary in their sexual behavior, and these differences correlate with expression levels of vasopressin receptors in reward areas of the brain. Scientists were able to change adult male montane voles' behavior to resemble that of monogamous prairie voles in experiments in which vasopressin receptors were introduced into the brain of male montane voles. See also Affectional bond Attachment theory Animal sexuality Breeding pair Human bonding Monogamous pairing in animals Monogamy r/K selection theory References Further reading External links Ethology Animal sexuality Evolutionary psychology