A mating system in which a male mates with more than one female, but the female mates with only one male. There are numerous examples across the animal kingdom, including some human societies. Polygynous males tend to be larger than the females, with sometimes marked sexual dimorphism, and compete with other males to secure access to females. Typically it is only the fittest, strongest males that mate and pass on their genes to the next generation, while weaker males are unsuccessful. The female’s offspring will thus benefit by receiving paternal traits that will maximize their fitness. Care of the young is undertaken mainly or exclusively by the female, although she may profit from the availability of resources, such as optimal nest sites or foraging areas, that fall within the territory defended by the male. Compare polyandry.