Squirrel Monkeys are some of the most common monkeys in South and Central American rain forests. They have a very large range throughout the Amazon and other rain forests. They live in groups of 10-70 but have been seen in groups as large as 100-300 individuals. The groups are split up into adult male bands, groups of mothers with their young, and juvenile bands. Mothers with their young seem to form the core of their society but neither males or females try to dominate. Adult males come around to intermingle with the females during the several months of year that mating occurs.

Squirrel monkeys are shy, non-aggressive and silent but make little squeaks and peeps at times and may shriek if they are in danger. They generally stay in the tree canopies but may occasionally come down to the ground to look for food. They have long tails which they use for support and balance as they are agile climbers and leapers. They also have hairy ears.