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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SOCIAL BEHAVIOUR AND PRIMATE EVOLUTION 425 societies suggests that the dominant male occupies a unique position, and that the area around him is a special region of the activity of the group ; this is because the oestrous females are in his vicinity. Owing to the fluctuating attractiveness of the females they pass into the sphere of the trigonal relations during oestrus, and pass out of it in dioestrus. Since during oestrus they mate only with the overlord, it should follow that all or most of the progeny at any one time are the offspring of the overlord and the females of the whole group. Mating, however, occurs between animals outside the trigonal sphere, but it is without breeding consequences. Thus, in its extreme form, this relation requires that for a male primate to produce offspring, he must occupy the overlord's position at least once in his life. In primates, therefore, the breeding/mating relations are dissociated. In this respect they are not alone amongst mammals ; the same essential relation is found in the herd of wild cattle observed by Darling (private communication) at Chillingham Park, but the other attributes of behaviour associated with successful breeding in herds of cattle are different. It should be noted that in primate society, a breeding premium is achieved by those animals whose attraction for the oestrous females is matched by an ability to withstand the conflict arising from the dominance of a more mature male. This ability to withstand conflict arises out of the constant equilibrational component present in their movements within the society, their stances, postures and carriage, and the absence of fighting in their behaviour. This means that these animals possess an ability to control aggressive responses under conflict. Selection of those animals which control aggressive behaviour in this region can be deduced from the disastrous effect of non-equilibrational behaviour on the fate of the maturing male primate. These are not restricted to a possible early demise, but mistakes in movements of the maturing male within the social field will affect his subsequent chances of reaching a sufficient degree of dominance to bring him within sight of the breeding position. (This is clearly a case of sexual selection as proposed by Darwin (1875) involving the intrasexual selection component distinguished by Huxley (1938).) This may be inferred from the work of Allee (1942), who has observed that success in fights makes for continued success, and failure for continued failure in fights between mice. If, as in primates, success in breeding depends upon sucess in a challenge, if not in a fight, then clearly those animals which do not challenge before the likelihood of success in a fight is reasonably assured will be more likely to reach a high status in the dominance hierarchy from which position most breeding is possible. There is more evidence bearing on this point. Miller (1950) has provided two examples of the conse-