Temporal patterning of sexual behavior in the male rat.

The copulatory behavior of male rats was described in terms of mount bouts, clusters of closely spaced attempts at mounting females, separated by periods free of mounting attempts. Measures based on mount bouts make possible meaningful temporal analyses of copulatory tests in which penile insertions (intromissions) do not occur during every mount bout. These measures were used to analyze the role of intromissions in governing the temporal patterning of the male's copulatory attempts. Prevention of intromission did not change the intervals between mount bouts significantly. Termination of mount bouts does not depend on intromission, and mounts without intromission strongly influence the timing of copulatory attempts. The temporal organization of mount bouts suggested that they might be basic units in the male's sexual behavior. The sexual behavior of rats and many other rodents is characterized by the male's repeated approaches to and mounts of the female. Most of the mounts lead to penile insertion (intromission), and after several intromissions ejaculation occurs. The approaches of male to female during such an ejaculatory series tend to recur at fairly regular intervals. However, little attention has been given to analysis of the factors underlying this aspect of the temporal patterning of the male's behavior. Such an analysis is essential to the formulation of a comprehensive theory of sexual behavior. Part of the reason for our relative lack of knowledge of the basis for the temporal organization is that the analysis of the timing of sexual behavior of rats has emphasized intromissions. As indicated before, mounts