Mates for Life? The More We Learn About Animal Sex, the Rarer True Monogamy Becomes

Stories of monogamous animals have a way of melting human hearts. You may have heard about lifelong swan partners, or watched the documentary March of the Penguins and shed some tears over the committed parents risking it all for their yet-to-hatch chicks. But monogamy in the animal kingdom is more circumstantial, complicated and often promiscuous than the standards we have for ourselves.