Black-handed spider monkeys are sociable animals and tend to live in multi-male, multi-female groups of 4 to 35 individuals (average around 15), although groups of up to 100 have been reported (2) (7) (8). These are fission-fusion communities, meaning that they usually split up into smaller subgroups to forage, particularly when food resources are scarce (6). This diurnal species relies heavily on a diet of fruit, but will also eat leaves, flowers, and occasionally bark, nuts, seeds, insects, arachnids and eggs (4) (8). Females actively choose their mates and initiate copulation, and breeding may take place at any time of the year (4). Females give birth to a single infant every two to four years, after a gestation period of seven to eight months (4) (9). Young are normally dependent on their mothers for three years, and reach sexual maturity at four years for females, five for males, after which females usually migrate to other groups (7).