The Evolution of Mating Systems in Birds and Mammals

The evolution of sex created a fundamental problem for nearly all plants and animals; namely, the need to fertilize eggs. Numerous types of mating systems have evolved as solutions to this problem, each molded by particular environmental circumstances and particular species attributes. Various hypotheses have been advanced to explain each type of mating system, but an integrated theory is only now beginning to emerge. Since mating behavior is affected by nearly all other aspects of an organism’s behavioral adjustments to its environment, such a theory must fit within a composite view of animal social behavior and hence must include explicit points of contact with related bodies of theory. In particular, mating system theory must mesh with theoretical advances concerning the evolution of territoriality, parental behavior, and animal sociality. By including the appropriate theoretical work from these other areas, an integrated theory of vertebrate mating systems can be developed.