The socio-sexual behavior of Japanese monkeys.

The sexual behavior of the Japanese monkeys of the Arashiyama B troop was studied in two mating seasons. Rank order of adult males (10 years old or over) had no positive correlation with mating activity. High-ranking males did not always attain high reproductive success. Some correlations were found between age, rank, and mating-partner selection. Some adult male-female dyads showed remarkable and long-term proximity. Some kind of psychological peculiarity is postulated within these dyads; although they were unrelated, most of them avoided mating, just as in related dyads. It is suggested that "affinity" may suppress the sexual drive, regardless of kin relationship.