In a manner similar to Georg Simmel’s call for the development of a “formal sociology” that studies generic forms of social organization and social interaction, evolutionary thinking has led to the development of a new, cross-species comparative sociology that is devoted to the study of “forms” of sociality that are distributed across species lines. By assuming a sociological point-of-view toward social behavior that is less provincial than that represented by traditional, mainstream sociology with its monospecific focus on humans alone, the new comparative sociology has featured cross-species analyses of phenomena such as the development of dominance hierarches among birds, fish, and primates and the existence of “vacancy chains” among invertebrates such as hermit crabs, octopuses, and crustaceans as well as vertebrates such as fish, birds, and humans. Vacancy chains refer to resources that are abandoned by current occupants and then used by a succession of other individuals, such as the shells occupied as residences by hermit crabs. Another phenomenon that has been explored by the new comparative sociologists is various forms of “social parasitism,” the structures and processes by means of which individuals usurp resources produced by others and exploit them to meet their own survival and fitness needs. Not surprisingly, social parasitism is often evident most dramatically in large complex social systems such as those represented by ant colonies and large-scale contemporary human societies. The focus in these sorts of cross-species comparative sociological analyses is less on individuals and more on the structures and processes that comprise social systems and the forms of sociality that they exhibit.