Female mating relationships in rhesus monkeys

Descriptions of the sexual behavior of social-living rhesus monkeys have indicated that mating patterns are characterized by the formation of consort pairs (mutually exclusive male-female associations) and also that females typically mate with multiple males. These reports raise the question of whether these are two different mating strategies or merely sequential phases in a unitary mating pattern. In order to examine this issue, the copulatory behavior of 27 adult females living in a heterosexual group housed in an outdoor compound was monitored both by group scan and focal sampling technique. Females displayed discrete periods of mating, characterized by one or more copulations per 4 hr observation period. During their sexually active periods, females copulated with multiple males (X̄ = 5.22, SE = 0.37). Among the 103 cases where females had multiple copulatory series on the same day, the successive series involved new males significantly more often than the previous partner. When a female did copulate repeatedly with a male on a given day, both she and her partner were significantly more often of high social rank. Furthermore, the interval between successive copulations was significantly longer when the second copulation was with her previous partner as compared to a different male. Analysis of female behavior for a one-hour period following a copulation indicated that females continued to be sexually active and that those new sexual interactions more often involved a new male. Thus, females not only copulated with multiple males throughout their inclusive period of sexual activity, but also interacted with multiple males on any give day they were sexually active. Since repeated copulations with the same male were rare and occurred when both members of the pair were high ranking, the consort relationship probably does not describe a characteristic mating strategy. The more pervasive pattern is for a female to sexually interact and have copulations with multiple males.