ABSTRACT
In the odyssey I have outlined in the preceding chapters, the OW monkeys provide us with a beginning point in which social organization and structure are explicable by reference to biological evolution driven by natural selection and biological kin selection. Within this context, social organization for the OW monkeys appears to be a balance between the opposing effects of predation risk leading to larger groups and resource competition at the level of individuals having the opposite effect, taking into account the way male-female relations play out in a particular species. For the female philopatric species, social organization revolves around female matrilines with biological kin selection for altruistic behaviors such as grooming. The combination of social units based on matrilines and a stable dominance relation among matriline units implies that social complexity scales with the number of matriline units, not the total number of females. Correspondingly, the neocortex ratio, taken as a measure of social complexity, differs systematically between modes of adaptation such as arboreal versus terrestrial foraging, and only indirectly with troop size.
