Female rhesus sexual behavior and distance to a male partner: relation to stage of the menstrual cycle.

Female rhesus monkeys were observed in standardized mating tests during successive menstrual cycles as well as in tests while separated from, but in view of, their male partners. Under both conditions, behaviors of the female were noted which varied with the stages of the menstrual cycle. Some of the most prominent fluctuations occurred in measures of interindividual distance. In particular, time spent near the male peaked at the time most likely for ovulation. The pattern of changes in this behavioral index followed a course similar to that noted for male ejaculatory success and for hormone-dependent coloration of the females; sex skin. The frequency of particular female solicit actions was also maximal during the perivulatory portion of the cycle. Female presents, a behavior often used by others as an indicator of female sexual motivation, did not show corresponding changes under either test condition.