Proximity, Sociality, and Observation: The Definition of Social Groups

It seems likely that individuals would be especially attuned to the kinds of social grouping that typically occur in their own species. Consider for example a male hamadryas baboon who herds females when experimentally transferred to a savanna baboon troop (cf. Kummer 1968). He acts as if he is establishing and protecting a harem, and responds to females in terms of whether or not they are members of his harem. When the females enter estrus, however, it is clear that the savanna males do not behave as if this harem exists; this "group" of females that is recognized by the hamadryas male is apparently not recognized by the savanna males.