Abstract and Summary
The significance of a one-male troop organization in determining the reproductive success of adult male guenons is called into question by the observations reported here. A previously habituated blue monkey (Cercopithecus mitis stuhlmanni) troop was observed for 6 months during which time 16 adult males associated with the troop and 9 were seen to copulate with about 6 of its 18 adult females which became receptive during the observations. For two years before the study there was only one adult male in the troop and the same male was again the only one present for several months afterwards. During the study this male ranked above all the others in terms of agonistic interactions, and copulated least frequently. The simple dichotomy between harem male and solitary male could not be applied in this population, and adult males were seen to maintain varied social relationships with each other and with the females of several adjacent troops.