The black spider monkey feeds on a wide variety of fruits, supplementing the diet with young leaves, flowers, buds, bark, honey, and occasionally small insects (1) (4) (5) (9). Like other spider monkeys, it is believed to be an important seed disperser (1) (4) (9). Spider monkeys are agile primates, capable of moving swiftly through the trees by swinging, climbing, running along branches, or even walking bipedally, and can even hang suspended by the tail, leaving both hands free for feeding (2) (4) (6) (7) (8).
Black spider monkeys live in a ‘fission-fusion’ society, in which groups of up to 20 to 30 individuals regularly divide into smaller, temporary subgroups, the only persistent relationship being between the female and offspring (2) (4) (6) (8) (9). Larger subgroups may form when fruit is more abundant, and the monkeys may travel large distances each day in search of food (2) (9). The female black spider monkey usually gives birth to a single young, after a gestation period of around 7.5 months, with births peaking between November and February in some areas. Spider monkeys have one of the slowest reproductive rates of all New World monkeys, the young remaining with the female for up to four or five years, and the female only giving birth about once every three to four years (1) (4) (5). On reaching maturity, young females may leave to join another group (2) (8). Lifespan is thought to be at least 33 years (4).