The agile mangabey lives in troops of around 8 to 22 individuals, usually led by a single adult male (1) (2) (6). The diet is varied and includes fruit, buds, seeds, shoots, leaves, mushrooms, insects and sometimes birds' eggs and small vertebrates (1) (6) (7). Adult males have even occasionally been recorded killing and eating young antelopes (9). The agile mangabey's large incisors and powerful jaws enable it to open tough nuts and pods which other monkeys are unable to exploit (5) (6), while cheek pouches allow food to be gathered for later consumption (6). Agile mangabeys breed year-round, the females giving birth to a single young after a gestation period of around six months (5) (6) (7). Like other mangabeys, the female agile mangabey develops a prominent sexual swelling as a visual signal advertising her readiness to mate (6).