Copulatory behavior of sexually inexperienced male guinea pigs paired with synchronized estrus females.

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.