Many studies demonstrate that the social behavior for one species frequently changes with differences in resource availability or even demographic fluxuations. This only reinforces the idea that primate social groups are the product of selection. Therefore, primate social groups have tended to evolve as a means for survival around a variety of reproductive strategies. Advantages and disadvantages are balanced through behavior responses that one finds in different primate social groups. Sexual Dimorphism and Size of Canines can be correlated to behaviors relating to social organization.
Sexual dimorphism is greatest and canines large in polygynous societies.
Even in size is the rule for monogamous societies. The following picture of a male and female gibbon skull show a remarkable size similarity reflecting the lack of competition in a male-female bonding behaviors among gibbons. Keep in mind that primate social organization is varied. It is becoming clear that there are differences between troops of chimpanzees or baboons.