Vasopressin (AVP) and oxytocin (OT) are key modulators of vertebrate social behaviour. Central infusion of AVP or OT promotes pair bonding and the distribution of vasopressin 1a (V1aR) and OT receptors (OTR) differs markedly between monogamous and polygamous species. For example, the monogamous prairie vole (Microtus ochrogaster) has higher densities of V1aR and OTR in prefrontal cortex, basal ganglia and the limbic system than the polygamous montane vole (M. Read more about Sociality in ground squirrels