Monk sakis are New World monkeys, from South America. They have black coarse fur, which is long and shaggy around the face and neck. Their hands and feet are light in color and the tail is thick and bushy.
Monk sakis are shy and wary animals. They are totally arboreal, living high in the trees and sometimes descending to lower levels but not to the ground. They generally move on all fours but may sometimes walk upright on a large branch and will leap across gaps. They are social and diurnal creatures. During the day, they move in pairs or small family groups spending most of their time feeding. One of the main forms of socializing between the family members is allogrooming (social grooming). Monk sakis communicate with each other with the help of different vocalizations. Adults recognize each other by using highly specialized vocalizations. To express aggression Monk sakis use squeaks, whistles, trills, barks, grunts, and roars.
Monk sakis are monogamous and pairs mate for life. Females give birth to a single infant during the breeding season. The gestation period lasts around 170 days. After birth the infant clings to mother's belly and closer to the weaning age it moves to her back.
Main threats to Monk sakis are hunting and the loss of the habitat. These animals sometimes also suffer from the pet trade.
The IUCN Red List and other sources don’t provide the number of the Monk saki total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.
Due to their diet, Monk sakis act as important seed dispersers of the fruits they consume. This way they benefit the local ecosystem.