Copulatory Behavior of Golden Hamsters (Mesocricet Us Auratus)

Abstract

Several experiments were performed in order to provide quantitative and qualitative descriptions of the copulatory behavior of syrian golden hamsters (Mesocricetits auratus) observed under laboratory conditions. The results of these studies indicate that: I. The male copulatory pattern may be generally classified as a multiple intromission, multiple ejaculation pattern with no copulatory lock and an absence of thrusting during intromission. The exception to this is the appearance of "long" intromissions, involving multiple intravaginal thrusting, as the male approaches satiety. The function of the long intromission appears to be to increase penile stimulation in the male. Significance of the long intromission for the female is unknown. 2. Behavioral criteria which allow ejaculations to be distinguished from other complete intromissions were identified. The most valid criterion was an increase in rate of preinsertion thrusting prior to ejaculation. It was also possible to use behavioral measures to identify the post ejaculatory interval. 3. Data from standard latency and frequency measures were quite similar with those of BEACH & RABEDEAU (1959). There was, however, an increase in ejaculation latencies and interintromission intervals as the male approached the satiety criterion. 4. The duration of intromissions during which ejaculations occurred was reliably, but not strikingly, longer than that of non-ejaculatory "regular" intromissions. The durations of "long" intromissions, during which no ejaculations were ever found to occur, generally exceeded the duration of both ejaculations and regular intromissions, but some overlap existed. "Long" intromissions could, however, be identified by multiple intravaginal thrusting behavior. In the first copulatory of a test, the first intromission was of longer duration than later intromissions. 5. Male golden hamsters exhibit renewed copulatory behavior after reaching satiation if another, previously unmated female is introduced into the test situation (Coolidge Effect). Female contributions to the regulation of satiety effects appeared to be extensive but were not analyzed in the present study. 6. In contrast to many other rodents, male behavior of golden hamsters is exceptionally channelized toward copulatory behavior during the ejaculation latency period. Also, in contrast to many other rodents, the duration of lordosis in female golden hamsters is very long. Other species typical differences were also observed. Several experiments were performed in order to provide quantitative and qualitative descriptions of the copulatory behavior of syrian golden hamsters (Mesocricetits auratus) observed under laboratory conditions. The results of these studies indicate that: I. The male copulatory pattern may be generally classified as a multiple intromission, multiple ejaculation pattern with no copulatory lock and an absence of thrusting during intromission. The exception to this is the appearance of "long" intromissions, involving multiple intravaginal thrusting, as the male approaches satiety. The function of the long intromission appears to be to increase penile stimulation in the male. Significance of the long intromission for the female is unknown. 2. Behavioral criteria which allow ejaculations to be distinguished from other complete intromissions were identified. The most valid criterion was an increase in rate of preinsertion thrusting prior to ejaculation. It was also possible to use behavioral measures to identify the post ejaculatory interval. 3. Data from standard latency and frequency measures were quite similar with those of BEACH & RABEDEAU (1959). There was, however, an increase in ejaculation latencies and interintromission intervals as the male approached the satiety criterion. 4. The duration of intromissions during which ejaculations occurred was reliably, but not strikingly, longer than that of non-ejaculatory "regular" intromissions. The durations of "long" intromissions, during which no ejaculations were ever found to occur, generally exceeded the duration of both ejaculations and regular intromissions, but some overlap existed. "Long" intromissions could, however, be identified by multiple intravaginal thrusting behavior. In the first copulatory of a test, the first intromission was of longer duration than later intromissions. 5. Male golden hamsters exhibit renewed copulatory behavior after reaching satiation if another, previously unmated female is introduced into the test situation (Coolidge Effect). Female contributions to the regulation of satiety effects appeared to be extensive but were not analyzed in the present study. 6. In contrast to many other rodents, male behavior of golden hamsters is exceptionally channelized toward copulatory behavior during the ejaculation latency period. Also, in contrast to many other rodents, the duration of lordosis in female golden hamsters is very long. Other species typical differences were also observed.