Evolution.

Society for Experimental Biology

Date:: 1953

Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Evolution. Source: Wellcome Collection.

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420 SOCIAL BEHAVIOUR AND PRIMATE EVOLUTION females coming into heat. Unlike the baboon females, which remain attached to one male in a number proportional to the dominance of the male, macaque females, after exhausting the copulatory potentialities of a low-ranking male, solicit the attention of other males higher up the scale by aggressive as well as sexually assertive behaviour. The change in their social status often calls forth attacks by still more dominant males, but in these encounters the male to whom the advance has been made often remains neutral. Moreover, his reluctance immediately to respond sexually is considered by Carpenter to be an expression of the restraining influence of the male dominance hierarchy on the behaviour of the subordinate males. It is possible, therefore, to show that the social relations of mature males is regulated by the dominance of one male over another in all species of infra-human primates on which observations have been made in the wild or in comparable free-ranging conditions. This dominance is exerted by threat which in many instances is directed by facial expression, but which may also be expressed in the body posture of the high-ranking males (Carpenter, private communication). The existence of relatively prolonged periods of stable relations within the group must, therefore, be ascribed to the dominance relations within it, and this implies in turn that one animal is suppressing his approach with respect to another. (b) Spatial behaviour patterns The factors that have been identified in primate societies provide the essential elements of conflict, as this was defined earlier. The sexual attractiveness of the female is matched and balanced by the threat of a more dominant male. It should, therefore, be possible to describe the social behaviour of primates in spatial terms, similar to those we found adequate for orientation behaviour about a single object where this is also the site of goal achievement. Zuckerman's description of the baboons suggests this. 'Family parties move independently of one another, and seldom come into contact. They act as separate groups in all their activities as a rule, mingling with other members of the colony only when engaged in communal feeding, or when participating in some quarrel ' (Zuckerman, 1932). Carpenter has described the characteristics in a way which confirms this inference ; An important clue to social relations in primate societies is the observed spatial relation of individuals, sub-groups or organised groups. The strength of the attachment between two individuals may be judged, or actually measured, by observing for a period of time the average distance which separates the two animals. In group i of the Santiago Rhesus Colony, for example, the most dominant male and the next most dominant male were on the average less