Spider monkeys are agile primates, capable of moving swiftly through the trees by swinging, climbing, running along branches on all fours, or even walking bipedally (1) (2) (4) (5). Fruit makes up over 80 percent of the diet, although young leaves, flowers, buds, bark, decaying wood, seeds, honey and occasionally small insects are also taken (1) (2) (4). Spider monkeys are thought to be important seed dispersers (1).
Although little information is available on the social and reproductive behaviour of the white-whiskered spider monkey, it is likely that, like other spider monkeys, it lives in a ‘fission-fusion’ society, in which groups of up to 20 to 30 individuals, of both sexes and all ages, regularly divide into small groups, with the only persistent relationship being between the female and offspring (1) (2) (4) (5). Breeding appears to occur year-round (2) (4), with the female spider monkey giving birth to a single offspring after a gestation period of between 200 and 232 days (4). The young spider monkey clings to the female’s belly at first, later riding on her back (6). Female spider monkeys reach sexual maturity at around four years, and males at five years, with young males generally remaining in the group, while females move out to join a new group on reaching maturity (2) (5). Spider monkeys reproduce relatively slowly, with the female giving birth only once every two to four years (2) (4). Lifespan may be more than 20 years in the wild (6).