Amazing Then & Now Couple Photos That Prove True Love Does Exist

Researchers have often investigated the influence of oxytocin and vasopressin in non-human animals such as the prairie and montane voles. It is clearly documented that prairie voles (which form monogamous lifetime relationships known as pair-bonds) have much higher densities of oxytocin and vasopressin receptors than the promiscuous montane voles, particularly in the dopamine reward system.