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.

443/484 (page 411)

SOCIAL BEHAVIOUR AND PRIMATE EVOLUTION 413 It should also be noted that under these conditions where encounters occur or where unfamiliar antagonistic components are present, mating behaviour becomes more and more an integral part of the social responses between primates. Beach (private communication) has noted that of 174 paired matings betvveen chimpanzees recorded by Yerkes & Elder (19366), one-third occurred outside the period of tumescent sexual skin. These matings are ascribed to social factors, amongst which dominance has been identified as in certain instances an important factor, after the observations were made on caged individuals. Elder & Yerkes (1936 è) make the following comment: Normally and typically the multiparous female will mate with a male with whom she is intimately acquainted and on friendly or affectionate terms only during a few days of the period of genital swelling about and including the sexual time of ovulation. At other times, the female as a rule is ignored sexually by the male, or, if approached or solicited, she avoids him. Every word in this statement is important, for social relationships as well as the physiological status of the consorts are important determinants of response. (Our italics.) If either mate be recently matured sexually, relatively inexperienced in mating, or if the two be strangers, slightly acquainted, or hostile mutually of one to the other, mating may occur under any condition of sexual status and seemingly irrespective of biological appropriateness and reproductive requirement, or on the other hand, it may not occur even under entirely appropriate physiological conditions? Moreover, Carpenter (19420) ascribes the prolongation of oestrus in the consorts of the dominant macaque males to the influence of dominance as well as to perseveration. Since in man the sexual propensities of the female are not dependant, as in subhuman primates, on fluctuating anatomical or behavioural features, her attractiveness for the male originates from the socio-sexual status of her behaviour. This represents the culmination of the process of the modification of sexual gestures and postures into overt forms of social communication, establishing socio-sexual status, which has originated in the primates. The development of flexibility in the control of sexual behaviour and the consequent reduction of control by stereotyped anatomical and hormonal mechanisms as a result of the transfer of function to cortical mechanisms is shown to be a pre-eminent evolutionary process in the progress from mammals, through subhuman primates to man, in a well-documented review by Beach (1947). In conclusion, it can be stated that the majority of contemporary primates exhibit a characteristic combination of reproductive features which create the possibility of continuous mating provocation. In no other mammalian