Table 1.

Summary of resource-based models and predicted effects of changes in resources on group size, mating systems, and spatial organization.

Model	Ecological variable to increase	Change in group size	Change in mating system	Change in home-range features	Advantage to sociality	References
Polygamy potential	Spatial distribution of resources	Increase	Monogamy → polygamy	Group defends 1 high-quality patch	Increase access to additional mates or resources	Emlen and Oring (1977)
Habitat-variability mating system model = resource defense	Patchiness and quality of resources	Increase	Monogamy → polygyny	Home-range size increases and group defends multiple high-quality patches	Increase access to high-quality resources	Slobodchikoff (1984); Travis et al. (1995)
Female dispersion– male behavior	Abundance and quality of food	Increase	Monogamy → polygyny	Home-range size decreases	Increase access to mates (for males)	Brashares and Arcese (2002)
Resource dispersion	Temporal and spatial heterogeneity, richness, and dispersion of resources	Increase	Not applicable	Home-range size increases	Neutral	Johnson et al. (2002); Macdonald (1983)