Uakaris have a diet of unripe seeds, an adaptation that allows these monkeys to inhabit a number of forests types that other primates cannot on a continual basis (11). Seeds of the tree species Micrandra spruceana, Eperua leucantha, and Hevea braziliensis are the most important food item, but the black-headed uakari will also eat fruit pulp, leaves and insects (1) (8). Traveling widely in large, flexible groups, the black-headed uakari moves up to four kilometres each day, but forages individually (7) (8). Although normally found in aggregations of around 10 to 30 individuals, large groups of up to 100 may be observed in areas of high food abundance (6) (8) (12). Group members communicate using a wide array of vocalizations, including screams and hissing, and visual signals, such as tail-wagging (7). Mixed sex, multiple male and multiple female groups have all been observed, but a dominance hierarchy has not been recorded yet (7) (10) (11).
Birthing in the black-headed uakari coincides with the onset of the rainy season, a period in which fruit productivity peaks, between March and April (7). A polygynous species, a single young is most likely born every two years, with the male reaching maturity at six years of age, and the female at three years (6).