The mating system and mating strategies of a species refer to the behavioral strategies used to obtain reproductive partners and ensure reproductive success. Common determining factors of mating systems and strategies are: the manner of mate acquisition, the number of mates obtained by an individual, as well as the absence or presence and duration of parental care. In mammals, the energetic investments in gametes and rearing offspring are typically larger for females than for males. Mate selection is thus a much more important decision for females than for the rather indiscriminate males. This dichotomy results in sexual selection, which in turn is determined by male–male competition for access to females, as well as female mate choice. Because receptive females are generally considered the limiting resource in reproduction, males face intrasexual competition for mates. In a multitude of mammalian species, including bears, this has resulted in pronounced sexual size dimorphism and polygamous mating systems. Despite common characteristics (e.g. sexual size dimorphism, polygamy), variation in mating systems and strategies occur among bear populations and species.