Male rats were given continuous access to estrous female rats for
24 hr each day for 10 days. During the first 12 hr, the rats
achieved an average of 10 ejaculations, followed by a 1- to 2-day
recovery period with little sexual activity. During the last 7
days, the rats maintained a reasonably stable equilibrium level
of 3 ejaculations per say. These occurred predominantly during
the dark phase of the diurnal cycle, they frequently occurred in
a cluster, and they usually occurred shortly after the introduction
of a novel estrous female. Except for quantitative differences,
these results are generally consistent with conventional research
but systematically extend the generality of the result to the
context of the free behavior situation. The availability of
sexual activity had no appreciable effect on food and water intake,
but it did decrease the amount of running activity.