species. Discrepancies in primate behavior in captivity and in nature have been noted by various studies, and some behavior in each setting that appears consistent with gaining individual benefit may not serve species survival but rather species extinction. For example, "rapes" have been observed by gorillas and chimpanzees in captivity but not in nature (Nadler, 1988; Thierry, 1997). On the other hand, infanticide has been observed in nature among African gorillas in Rwanda (Zimmer, 1996). Meanwhile, grooming behavior, most of it between aging troop members of the same sex, has been particularly noted in studies of chimpanzee and baboon troops. Grooming has been interpreted as evidence of socialization in nature (Stammbach, 1987), but it has also been observed in captivity (Sambrook, Whiten, & Strum, 1995).
How does one form of behavior but not another, or how do two disparate forms, develop in primate groups? Is behavior solely idiosyncratic and opportunistic, solely directed toward gratification or protection? Or do social norms operate in specific ways. And if survival of the species is instinctual in primate groups, do social norms or individual behavior have a greater role to play in the actions that are an attribute of that instinct? Does social organization per se affect species survival?
A sharper understanding of the role of social organization, if any, in shaping behavior that fosters evolutionary survival of the species would be helpful. The purpose of this study is to test the hypothesis that primate survival strategies serving the continuation of the species develop in the context of social organization characterized by multiple and genetically diverse family units rather than by isolated or only closely related family units. To put it another way, it is hypothesized that species survival is chiefly served by a community of strangers with whom genetically diverse individual and family units both compete and cooperat...