CHARACTERISTICS OF THE MOTOR AND GENITAL COPULATORY RESPONSES OF THE MALE HAMSTER

The temporal and dynamic characteristics (duration, frequency, rhythmi city, and vigor) of pelvic thrusting displayed by 17 male golden hamst ers during their copulatory behavioral responses: mounts, intromission s, ejaculations, and long intromissions, as well as their temporal cor relation with the genital contacts established by intravaginal penile insertion, were studied by an accelerometric and polygraphic technique . Pelvic thrusting in all copulatory behavioral responses appeared as series or trains of rhythmical, synchronic, vigorous movements. The va rious pelvic thrusting trains lasted around 1 s on average, but those of mounts were signifi cantly longer than the trains displayed in the other behavioral responses. The frequencies of pelvic thrusting were s imilar in all responses (around 15 thrusts per s) excepting mounts whi ch had lower values. In intromission, ejaculation, and long intromissi on responses, when penile insertion occurred, pelvic thrusting either was interrupted or showed changes in its characteristics: penile inser tion was related to a period without thrusting in intromissions, to a series of intravaginal thrusting of higher frequency (16.4 thrusts per s) and lower vigor in ejaculations, and to a prolonged period of 6 to 25 s of slow intravaginal pelvic thrusting (1-2 thrusts per s) in lon g intromissions. Penile insertion lasted longer in ejaculations than i n intromissions and it was significantly shorter in both of these resp onses than in long intromissions. These results provide information ab out some dynamic aspects of sexual behavior in hamsters, as well as a temporal correlation between the motor and genital components of this behavior.