Peruvian spider monkeys are relatively large among species of monkey, and their strong, prehensile tails can be up to 1 meter long. Their fur and face are black in color. Peruvian spider monkeys have four elongated fingers and virtually no thumb, which is typical for spider monkeys but unusual for other monkeys. They can move easily through the trees and have a prehensile tail, which these monkeys use to assist with brachiation (swinging from one branch to another using only their arms).
Peruvian spider monkeys are found in central-northern of Bolivia, north-eastern Peru, and the central-western Brazilian Amazon. They were recently found to occur in the northern bank of Solimões River, at the Mamirauá Reserve (Brazil). Peruvian spider monkeys live primarily in lowland forests, occupying the canopy and the sub-canopy, but they may use various habitat types, including dry and hilly areas such as the piedmont and cerrado forests. They were also observed living in Amazonian seasonally flooded forests.
Peruvian spider monkeys arboreal and diurnal creatures. During the day they spend their time feeding, resting, moving around and grooming. When these monkeys travel around their territory they spend most of the time climbing, hanging from branches, moving by brachiation and arm swinging. They rarely walk or run on all fours. Peruvian spider monkeys live in bands of 20-30 individuals, but these bands rarely stay all together and average size is usually 3 individuals. Band size is somewhat seasonal, probably because of food availability and because females separate themselves from the band for a few months to give birth, primarily in the fall. In order to communicate with each other Peruvian spider monkeys use grunts, howls, or screams. Mates usually recognize each other through smell. These spider monkeys also shake tree branches and may signal each other by swinging their arms.
Peruvian spider monkeys are polygynandrous (promiscuous) and both males and females have multiple partners each breeding season. These monkeys can breed throughout the year though most infants are born at the start of the autumn season. Females give birth to a single baby after the gestation period of about 140 days. The pregnant female leaves the group to have her baby and returns 2-4 months later. Newborn infants spend most of the first 10 months of their life with their mothers. Young either cling to mothers' bellies or ride on their backs. Mothers protect and nurse them. When infants are 10 months old, they can travel independently, but still stay not far from their mothers. Peruvian spider monkeys become reproductively mature at 4-5 years of age.
Peruvian spider monkeys are threatened due to exploitation by humans and habitat loss. The decline in their populations is partially due to the fact that these monkeys are targeted by hunters for sale and consumption in the Amazonian bushmeat trade. Furthermore, habitat in the southern part of their range is being developed for agriculture and habitat in the southwestern Peruvian region of Madre de Dios is being polluted and destroyed by illegal mining activity. In Peru, illicit extraction of timber and wildlife products remain issues even in protected areas.
The IUCN Red List and other sources don’t provide the number of the Peruvian spider monkey total population size. Currently, this species is classified as Endangered (EN) on the IUCN Red List and its numbers today are decreasing.
Due to their foraging habits, Peruvian spider monkeys are the vital seed dispersers for many tree species in Amazonia.