Birds are the exception in the animal kingdom – 90 per cent of species enter into monogamous relationships. Monogamy in the animal kingdom is rare – because it is not essential for reproduction. So, why is monogamy found in so many species? At least 12 genes play an important role in mating strategies in the animal kingdom: some change partners, others mate for life or at least for a breeding season. Monogamy has emerged many times in the course of evolution, so monogamous s