The Guianan squirrel monkey is a small species of squirrel monkeys that have gray fur on most of their bodies but have more yellow/orange fur on their backs and limbs, with white on their belly. Their long tails, usually measuring anywhere from 14 to 19 inches, is gray with black at the end.

Their body length measures about 9 to 14 inches long and they weigh 1 to 3 pounds. These small monkeys have a round head with a light pink face, white arches over their eyes, and black around their mouths.

Guianan squirrel monkeys live in tropical forests in countries like Brazil, Guyana, Suriname, and French Guiana. Though they will live in any type of forest, they prefer primary and secondary forests. Meaning they prefer forests that have either not been disturbed at all or have been disturbed a little bit.

Spending most of their time in trees, Guianan squirrel monkeys go from tree to tree foraging for food and occasionally taking breaks with their group to rest and socialize.

Guianan squirrel monkeys are omnivores and eat a wide variety of food. Most of which consists of fruit, leaves, seeds, flowers, and nectar. Though on occasion, they will eat different types of insects like spiders, and arthropods, like centipedes. Although it is not normal, they have been seen eating small vertebrates like birds and bats.

The Guianan squirrel monkey spends their days foraging, along with other monkeys like the bare-eared squirrel monkey, the red-backed bearded saki, and capuchin monkeys.

Most mating between Guianan squirrel monkeys happens between the months of September to November. Males tend to gain weight and become more aggressive before mating season.

Females are pregnant for about 5 months and all of the young are usually born in the same time span in January or February. The mother cares for the baby alone, as the males provide no parental care. Females with no young are known to help care for some young. Females reach sexual maturity at around 3 years of age, males however are not mature until 5.

Guianan squirrel monkeys live in groups with sometimes up to 300 members! By sticking together, they can protect themselves from danger and their food/resources from potential rivals.

Because they mingle quite a lot with the capuchin monkey, who tends to be more on the lookout for danger, the Guianan squirrel monkey will listen to their alarm calls and run to protect itself from potential danger. Unlike most animals, females hold the dominant positions in the group. Males have their own hierarchy which determines who is allowed to mate.