Brown woolly monkeys are large primates that belong to the New World monkey family. Contrary to their name, they may also be a shade of grey or black as well as brown and are darker on the head and underparts. Their fur is soft, short and thick. Their face is naked of any fur and is typically black. Brown woolly monkeys have long limbs and prehensile tail, which help them to move easily through the forest. Most male woolly monkeys are larger than the females and have larger canines.
Brown woolly monkeys are found in the upper Amazon basin in South America, ranging from the Rio Tapajos in Brazil to eastern Peru, Ecuador and Colombia. They live in the rainforest, usually in the canopy of the tallest trees, though they may also be found at shrub layer. In certain seasons they may also enter flooded forests, due to a higher concentration of berries.
Brown woolly monkeys are arboreal and diurnal. They spend a large amount of time eating and moving in the pursuit of food, covering roughly 2 km per day. When feeding these monkeys often use their tail for hanging and gripping; they also use it for playing and even can pick up objects with it. When moving on the ground Brown woolly monkeys use all four legs for walking/running and climbing. They live in groups of 2 to 70 individuals, usually splitting the group into smaller subgroups when active. Larger groups consist of family units that may feed and travel together or separately but will come together to sleep at night. Brown woolly monkeys often groom each other and communicate with the help of vocalizations, facial expressions, and other behaviors. These monkeys are very loud and their calls sound like barks or screams. These calls are often used as a danger-signal to the rest members of the troop.
Brown woolly monkeys are omnivorous animals. They eat both plants and other animals. Their diet primarily consists of fruit, but they will also eat leaves, seeds, nuts, flowers and nectar, and even insects, small rodents and reptiles.
Brown woolly monkeys are polygynous which means that males mate with multiple females during the breeding season. Females give birth to a single infant after the gestation period that lasts 7-8 months. During the first month after birth the infant is carried on its mother's belly and by 6 weeks of age, it will be able to climb the mother's back. The mother will nurse her infant for 9-12 months. However, the baby woolly monkey becomes more independent at the age of 5-6 months. Females reach reproductive maturity when they are 6-8 years of age and males become reproductively mature at 5 years of age.
The biggest threat for Brown woolly monkeys is human activity, particularly the building of new highways through parts of the Amazon and the attendant deforestation. This leads to displacement and provides new access into the forests, creating the opportunity for more hunting to occur. Hunting is mostly carried out by the indigenous communities of this region of the Amazon. Its large size makes the Brown woolly monkey highly susceptible to being hunted by locals. Individuals may also be sold locally as pets.
The IUCN Red List and other sources don’t provide the number of the Brown woolly monkey total population size. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List and its numbers today are decreasing.
Brown woolly monkeys act as effective seed dispersers due to their frugivorous diet. This way these monkeys benefit the local ecosystem.