Their 6- 8 kg body is easily supported by a single limb or by their prehensile tail. The tail is also used for swinging and to pick up objects.
Spider monkeys are second in agility only to the gibbons of Asia.
The monkeys are diurnal with feeding typically done in the morning hours. As a species hunted by man, they are typically wary of researchers. Before becoming accustomed to the newcomers, spider monkeys have occasionally broken off heavy tree limbs to drop on these suspicious intruders. Prefer the middle and upper canopy of the forests. Group size seems to fluctuate greatly.