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Within the larger home ranges of breeding foxes (alpha-individuals), also nonbreeding females (beta-females) with smaller home ranges, occur. Within each group, beta-females are presumably related to each other and to the alpha-individuals. Beta-females exploit suboptimal habitats, thereby avoiding competition with the alpha-individuals, which mainly utilize optimal habitats. After one breeding female died, a non-breeding female raised the deserted cubs. The non-breeding females regularly become pregnant, but abort or desert their young. By this type of female cooperation, offspring survival and inclusive fitness is maximized. In contrast, subadult males, that cannot contribute to inclusive fitness in this way, instead emigrate from their natal home range, competing for optimal habitats. One subadult female with a small number of suboptimal prey items within her home range, also emigrated.
Schantz et al. (Wed,) studied this question.