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.

446/484 (page 414)

4l6 SOCIAL BEHAVIOUR AND PRIMATE EVOLUTION The socio-sexual relations of the gibbons would appear to be an example of this, since a state of low motivation might leave acquired bonds between animals of the same age group to determine the mating preferences of the young male. In the family parties of gibbons, dominance, which is seldom manifest, is not found predominantly in conjunction with competition for the same female, though this does occur (Carpenter, 1940). The main effect of dominance is to exclude the maturing male from the group. The fact that mating behaviour is a part of a primate's repertoire of activity enabling copulation and foreplay components to be initiated at any time in the cycle, makes it likely that the relation between the sexes will be more flexible than in lower mammals. This is true of the gibbons, howler and spider monkeys (Carpenter, 1934, 1935) in contrast to the baboons (Zuckerman, 1932) and macaques (Carpenter, 19420), and a greater individual variation in reactions is evident in the individual behaviour of the chimpanzees reported by Yerkes & Elder (1936Ô). In these circum¬ stances initiatory, aggressive, antagonistic and receptive behaviour may be shown by animals of either sex in their mating behaviour. On the other hand, the amount of interference between animals of the same sex for access to a member of the opposite sex is likely to be pronounced where the attractiveness of the female is high, or lasts at a moderately high level for a long time. Since the interference will be highest where attraction is most pronounced, we shall expect to find dominance exerting a marked influence when pronounced sexual activity is present. This will be more marked when more than one female is in oestrus at the same time (mating provocation type II, see Table i). With lower degrees of motivation or with a rapidly varying intensity of sex drive, some degree of alternating mating may participate alongside dominance in the control of this aspect of social acitvity, e.g. spider and howler monkeys. The mating provocation of primate societies constitutes what we have termed a bivectorial situation between the attractive female, and two or more males. In these circumstances we have noted that the behaviour of the two males must either be regulated by sequential mating or by some form of exclusive matings. These exclusive associations may either be the result of previous conditioning, or of dominance. The evidence from studies in the wild goes to show that dominance plays some part in many species, and a very prominent part in regulating the socio-sexual behaviour of the group in others. Dominance or the type of behaviour, which gains preferential access for the animal manifesting it, can be identified in every sphere of primate social life. It controls feeding behaviour in many species, and can be seen to influence the play of many young primates. It is also exerted between