Sexual behavior and reproduction of Cercocebus albigena johnstonii in Kibale Forest, Western Uganda

Gray-cheeked mangabeys live in multimale social groups. Two groups of these monkeys were studied extensively over a period of 22 months, and a further eight groups were observed opportunistically. Data on the occurrence of sexual swelling in females were collected and the different phases of swelling and deflation are described in detail together with data on their duration. The data were found to agree broadly with those presented by other workers on captive animals. Pre- and postpartum swellings are described. The majority of copulations was observed to occur at peak swelling and a specific gesture, the head flag, was noted as a solicitation. The data on initiation of copulations show that the males initiated more copulations than the females. The data show gestation periods of between 184 and 189 days. A mean interbirth interval was calculated to be 33.33 plus or minus 15.87 months.