The red-backed squirrel monkey (Saimiri oerstedii) is the smallest in size and also occupies the smallest area of the 4 species of monkeys found in Costa Rica. It mainly inhabits secondary forests and partially cleared primary forests. It is omnivorous - its diet includes insects and their larvae, fruits, seeds, flowers, and even nectar. They form groups averaging 40 individuals, occupying an area of up to 60 hectares. They are adorable, active, and in my opinion, the prettiest monkeys in Costa Rica :)