Territoriality

Territoriality, one of several mechanisms by which animals control access to critical resources, such as food or nesting sites. Males typically compete for territories, either fighting actual battles or performing ritual combats as tests of strength (see Aggression). Weaker individuals may be excluded from holding a territory or be forced to occupy less desirable situations.

Territoriality may serve as a mechanism to distribute resources disproportionately to the strongest (and presumably the fittest), and to limit the reproduction of the less fit. At one time it was thought to involve the generous sacrifice of the excluded animals for the good of the group. The leading advocate of this view, the English zoologist Vero Copner Wynne-Edwards, argued that such “group selection” evolved for the cumulative genetic good of the species. The theory, although incorrect, was crucial in drawing attention to the difficulties that evolutionary theory had in accounting for the phenomenon of altruism, in which one animal sacrifices itself or its opportunity to reproduce to benefit others. It sparked the discovery of the currently favored theories of “kin selection,” reciprocal altruism, and other mechanisms that indicate that evolution operates on individuals rather than on groups. See Animal Behavior; Sociobiology.