Abstract
The copulatory behavior in sexually inexperienced male guinea pigs aged 12 weeks was observed under dim red illumination. The synchronized estrus females, which were used for receptive females, received a subcutaneous implantation of progesterone-filled tubing for 2 weeks, followed by 0.5mg progesterone injection. Females given these treatment exhibited the lordosis behavior at 19: 00 and 21: 00 h on 4th day, and had ovulated by 09: 00 h on 5th day after removal of implant. During a 2-hrs test session, standard measures of copulatory behavior were recorded. The ejaculation could be observed within the first 30 min in 6 of 7 males. The mounts, intromissions and ejaculation in male guinea pigs were shown in a lower frequency and longer latency than those of rats and hamsters.