Sexual Behaviour and the Vaginal Cycle in the Cat

Abstract

DIFFICULTIES have been encountered in studying the neural and endocrine mechanisms which underly the control of sexual behaviour in the mammal for two main reasons. First, conspicuous and easily observable patterns of stereotyped behaviour, which are uninfluenced both by learning processes and the conditioning effects of the experimental situation itself, are rather few among laboratory mammals. Innate reflex patterns of behaviour similar to those successfully utilized by ethologists in lower animals, that are stable and difficult to disturb, occur quite infrequently in higher forms. The sexual behaviour of the female cat is a conspicuous exception to this. Though Marshall has emphasized the virtual impossibility of determining the state of the sexual cycle in many species by external signs alone, the present study shows this is not the case in the cat. The second source of difficulty arises from the observation that some of the components of the total pattern of sexual behaviour may not be dependent upon the secretory activity of the gonads; this is most evident in the male, but is also quite apparent in the female of several mammalian forms. The female chimpanzee may accept the male at any time in her cycle (Yerkes and Elder¹); similar behaviour has been observed in the female rat (Boling et al. ²); and acceptance by both diœstrous and ovariectomized rabbits is well established^3,4. Sexual receptivity and the associated postural responses cannot be regarded as depending solely upon ovarian hormones in these species. This makes for difficulties in the interpretation of behavioural changes which appear to follow hormone administration. However, earlier studies by Bard⁵ have indicated that the full pattern of sexual behaviour of the female cat may be strictly dependent on hormones.