Here we attempt to define a specifically human ecology within which male re
productive strategies are formulated. By treating the domestic and public s
pheres of social life as "ecological niches" that men have been forced to c
ompete within or to avoid as best they can, we generate a typology of four
"social modes" of human male behavior. We then attempt to explain the broad
distribution of social modes within and between human groups based on the
relative intensity of scramble and contest competition.