It formerly included the sooty mangabey as a subspecies. The black crested mangabey ("Lophocebus aterrimus") is a species of primate in the family Cercopithecidae. Another primate, the gray-cheeked mangabey, seems to have recently become extinct in the area. The Uganda mangabey is rather smaller than the grey-cheeked mangabey ("L. albigena"). It was previously considered a subspecies of the agile mangabey ("C. agilis"). The agile mangabey has a short, overall dull olive-grey pelage. Three subspecies of this mangabey were previously recognized. As presently defined, the collared mangabey is monotypic. The grey-cheeked mangabey lives in groups of between 5 and 30 individuals. Until 1978, it was considered a subspecies of the Tana River mangabey ("C. galeritus"). The Tana River mangabey is diurnal and semi-terrestrial. One of the largest populations of Uganda mangabey is in the Mabira Central Forest Reserve. The collared mangabey lives in large groups of 10 to 35 individuals including several males. This is also the case with the Tana River mangabey. Animals on exhibit include red-capped mangabey, black mangabey exhibits.