Common Squirrel Monkey
Common squirrel monkeys are considered both frugivorous and insectivorous, preferring berry-like fruit on branches. Squirrel monkeys also look for insects and small vertebrates, such as tree frogs. It obtains a majority of its water from the foods eaten and also obtains water from holes in trees and puddles on the ground. When fruit is scarce, the common squirrel monkey drinks nectar.
Common squirrel monkeys are polygamous with a multiple-male, multiple-female group structure. Most social interactions in S. sciureus groups occur within the various age/sex classes, with the division of classes being between adult male categories, mother-infant categories, and juvenile categories. The core of the group is made up of adult females and their young. As a result of the natural attraction each class has to the adult females, the different age/sex classes come together as one social group.
Common squirrel monkeys are diurnal. They are usually quiet but will utter loud cries when alarmed. They use different types of calls for specific situations. Some of their common call types include caws, bawls, and shrieks. Squirrel monkeys utter caws mostly when they are trying to defend a territory. They may use bawls prior to a fight, as well as after one. Shrieks are mainly heard when the monkeys are fighting for dominance.
Squirrel monkeys urinate on their hands and feet as a form of scent marking. They then engage in urine washing by rubbing the urine on other parts of their bodies. There are many theories as to why squirrel monkeys engage in this behaviour, including leaving their scent behind as they travel through the branches to mark territory and to help separated troop members find each other. It may also be used to control body temperature, display dominance and as a way for squirrel monkeys to clean themselves.