Animal
Common squirrel monkey
The common squirrel monkey is a small, busy monkey. It has a white mask and yellow hands. It lives in big, noisy groups in the rainforest.
The common squirrel monkey is a small, quick monkey from the rainforests of northern South America. It has a white mask around its eyes, a dark muzzle and yellow-orange arms. Squirrel monkeys live in big, chatty groups and eat fruit in the wet season and lots of insects in the dry season.
Saimiri sciureus, now often called the Guianan squirrel monkey, lives in the Guianas and northern Brazil. Genetic studies split the old "common squirrel monkey" into several species, leaving this one with a much smaller range. A lively, insect-hunting primate of large groups, it is listed as Least Concern (IUCN, 2021), though its numbers are falling.
Photo: Mike's Birds from Riverside, CA, US, CC BY-SA 2.0, via Wikimedia Commons
Meet the squirrel monkey
The squirrel monkey is a small monkey.
It has a white face mask and a dark nose and mouth. Its arms and hands are yellow.
The common squirrel monkey is about as long as a ruler, not counting its tail, and weighs well under a kilogram and a half. Its tail is even longer than its body.
Look at its face: a white mask circles the eyes, and the dark cap on its head dips down into a little point between them. Its nose and mouth are a big black patch. Its back is yellow-brown, and its forearms and hands are bright yellow-orange. White tufts of fur cover its ears, so they look like pointed elf ears.
Saimiri sciureus is slender and long-limbed: head-and-body length is about 26.5 to 37 centimeters and the tail adds 36 to 45, while adults weigh 500 to 1,250 grams, females averaging about 635 grams and males about 740 (New England Primate Conservancy).
It belongs to the "gothic" group of squirrel monkeys: the dark cap forms a sharp, high V into the white eye mask, unlike the rounded "roman" arch of the black-capped species. The black muzzle is framed by white fur, white tufts cover the ears, and yellow-brown back fur runs to a black tail tip, with yellow-orange forearms and hands.
Quick facts
- Group
- Mammal
- Length
- 26.5 to 37 cm
- Weight
- 0.5 to 1.25 kg
Where it lives
Squirrel monkeys live in South America.
They live in warm, rainy forests. They also live in forests that are growing back.
Common squirrel monkeys live in the northeast of South America: in French Guiana, Suriname, part of Guyana and northern Brazil, mostly north of the Amazon River.
They live in tall rainforest and in forest with lots of palms and climbing vines. They also do well in forests that have grown back after trees were cut. The dry season there usually runs from June to November and the wet season from December to May.
The squirrel monkey in our photo lives somewhere very different: in a garden in Florida, far from its real home.
Older books gave the "common squirrel monkey" a huge range across the Amazon. Genetic and behavioral studies now recognize several separate species, so Saimiri sciureus in the narrow sense is found throughout French Guiana, in Suriname, southeastern Guyana and Brazil north of the Amazon and east of the Rio Branco (New England Primate Conservancy). The IUCN assessment also lists several Brazilian states south of the river (Maranhão, Mato Grosso, Pará and Tocantins), so where exactly the species' southern limit lies is still being worked out.
It uses lowland terra firme forest with palms and lianas, tropical rainforest and regrowing secondary forest, where it seems to thrive. Squirrel monkeys in general are habitat generalists that tolerate logged, edge and disturbed forest (Primate Info Net). Wild-looking groups in places such as South Florida were brought there by people.
Continent
Its habitat
Where can you find this animal?
- Lives here naturally · Countries and seas named by a scientific source
- Sightings recorded · Records of wild sightings (GBIF)
Lives here naturally · Countries and seas named by a scientific source
Rainforest and regrowing forest in Suriname, southeastern Guyana and northern Brazil, mainly north of the Amazon River and east of the Rio Branco. It also lives throughout French Guiana, which has no separate shape on this map. Squirrel monkeys in Colombia, Peru, Ecuador and Venezuela now belong to other species.
Places: Suriname, Guyana and Brazil.
Source: iucn-red-list · checked October 2026
Sightings recorded · Records of wild sightings (GBIF)
Counts of GBIF records of wild observations (human and machine) and preserved specimens. Records include introduced populations, vagrants, escaped or released animals and misidentifications, so a country with records is not necessarily part of the native range.
Wild sightings have been recorded in Colombia, Brazil, Ecuador, Suriname, Peru, Guyana, United States, Bolivia and 13 more places.
Source: gbif · checked October 2026
Range maps show where scientists say an animal lives, often country by country. An animal may live in only part of a country shown, and sightings records can include animals that wandered far from home.
Fruit and bugs
Squirrel monkeys eat sweet fruit.
When fruit is hard to find, they eat lots of bugs. They look for bugs hiding in dry leaves.
In the wet season, when the forest is full of fruit, squirrel monkeys eat as much sweet fruit as they can. In the dry season they switch to insects. They are the most insect-eating of all the monkeys of Latin America.
They are good at grabbing insects, and they have learned to unroll dead, curled-up leaves to find bugs hiding inside. They like caterpillars and grasshoppers best. They also eat nectar, flowers, seeds and sometimes bird eggs.
The diet follows the seasons: sweet fruit in the wet season, mostly insects in the dry season. The New England Primate Conservancy calls squirrel monkeys the most insectivorous of the Latin American primates; they pounce on insects and unroll dead leaf curls to check for hidden prey. Nectar, flowers, shoots, seeds, bird eggs, small birds and bats are also eaten.
Primate Info Net adds that squirrel monkeys prefer caterpillars and grasshoppers, mostly take insects sitting still on plant surfaces, and choose small, soft, berry-like fruits less than a centimeter across. By dropping or swallowing seeds, they help forest trees spread.
Did you know?
Boy squirrel monkeys get chubby before they look for a mate.
Before the mating season, male squirrel monkeys put on extra weight in their arms and shoulders, so they look puffed up.
Males gain about 85 to 222 grams before the mating season, mainly in the upper arms, shoulders and torso, giving a "fattened" look.
Built for leaping
Squirrel monkeys run and jump in the trees.
Their long tail helps them balance. Their long fingers hold on tight.
Squirrel monkeys run along branches on all fours and leap through the lower part of the forest. Their back legs are long, which helps them jump.
Many South American monkeys can grab branches with their tails, but squirrel monkeys cannot. Instead, they hold the long tail steady to help them balance. Long fingers wrap tightly around branches, but their thumbs cannot press against their fingers the way ours can, so peeling tough fruit is hard for them.
Squirrel monkeys move quadrupedally and leap in the understory; their hindlimbs are proportionally longer than those of other Latin American primates. The tail is not prehensile but is held steady at a low angle as a balance aid. Long fingers give a strong "power grasp", but the lack of a fully opposable thumb limits fine handling and fruit peeling (New England Primate Conservancy).
In the field, Primate Info Net reports that squirrel monkeys prefer to travel on branches only 1 to 2 centimeters thick and are rarely seen leaping horizontal gaps wider than about two meters.
Seeing colors
Boy and girl squirrel monkeys see colors in different ways.
Boys cannot tell red from green. Some girls can.
Squirrel monkeys do not all see the same colors. Every male is red-green colorblind, so red and green look alike to him.
Females are different: some see colors the way males do, and some see a full range of colors, like most people. Which one a female gets depends on the color genes she inherits from her parents.
Color vision in squirrel monkeys is polymorphic. The genes involved sit partly on the X chromosome, so males, with one X, are always dichromatic (red-green colorblind), while females, with two, may be dichromatic or trichromatic depending on the versions they inherit (New England Primate Conservancy, citing Jacobs and Neitz 1987).
Did you know?
Squirrel monkeys listen to capuchin monkeys to stay safe.
Squirrel monkeys react more strongly to capuchin monkeys' warning calls than to their own.
In mixed groups, squirrel monkeys respond more strongly to capuchin predator alarms than to conspecific calls.
Growing up
A mother squirrel monkey has one baby.
The baby rides on her. Other monkeys help carry the baby too.
Squirrel monkeys have their babies at one time of year, usually in the rainy season. After about five and a half months, a mother has one baby.
At about eight weeks old, the baby starts playing away from its mother and making friends in the group. Other members of the group, often related females, help watch or carry it. The baby stops drinking milk before its first birthday. Females can have babies at about two and a half to three and a half years old, and males are grown up at about three.
Breeding is strongly seasonal: the mating season lasts two to eight weeks, and births fall in the rainy season or late in the dry season. Gestation averages about 170 days and produces a single infant (New England Primate Conservancy).
Infants begin playing away from the mother at about eight weeks and are weaned in just under a year. Allomothering, in which other group members, usually related females, carry or watch the infant, is fairly common. Females reach reproductive age at about 2.5 to 3.5 years and can breed for up to about 16 years; males mature at about three. Squirrel monkeys can live to about 30, though mainly in captivity.
A busy, chatty group
Squirrel monkeys live in big groups.
They chirp and squeal to talk. They often travel with bigger monkeys called capuchins.
Common squirrel monkeys live in big groups of about 25 to 75. They spend most of the day looking for food, starting in the middle of the trees in the morning and moving down into the shade in the afternoon. At night the group sleeps close together in the same tree.
They are very chatty, with chirps, squeals, clucks and twitters. They often follow capuchin monkeys, picking up fruit the bigger monkeys drop. They even listen for the capuchins' warning calls about predators.
Groups of 25 to 75 are typical, but fewer than 20 may remain in isolated forest fragments. Males are usually dominant to females and stay at the edge of the group; female hierarchies are hard to see, and because food is patchy in this species' range, females compete over it more than in other squirrel monkeys (New England Primate Conservancy; Primate Info Net).
Calls include contact chirps and squeals, clucking, yapping and alarm peeps, growls, and twittering that strengthens bonds. Squirrel monkeys associate with capuchins at fruiting trees, gaining dropped fruit and early warning: they respond more strongly to capuchin predator calls than to their own.
Did you know?
A squirrel monkey's tail is longer than its body!
A squirrel monkey's tail can be up to 45 centimeters long, longer than its head and body.
Tail length (36 to 45 centimeters) exceeds head-and-body length (about 26.5 to 37 centimeters).
Keeping them wild
There are still many squirrel monkeys.
But people catch some to sell as pets. Wild monkeys belong in the forest.
The common squirrel monkey is listed as Least Concern: it copes well with forest that has been cut and grown back. Even so, its numbers are going down.
People rarely hunt squirrel monkeys for food, because they are so small. The big problem is that people catch them to sell as pets or for laboratories. An international agreement called CITES controls trade in them, and refusing to buy or share videos of pet monkeys helps too.
The IUCN lists Saimiri sciureus as Least Concern (Silva Junior and colleagues, 2021, an amended version of the 2020 assessment), but the population is decreasing. Its tolerance of disturbed forest helps it fare better than many Neotropical primates in the face of deforestation.
The main threat is live trade, legal and illegal: squirrel monkeys are among the primates most affected by the pet and biomedical trades. They are listed in Appendix II of CITES, but weak enforcement and loopholes let trade continue (New England Primate Conservancy).
IUCN Red List
How is the common squirrel monkey doing in the wild?
- Least Concern (this animal)
- Near Threatened
- Vulnerable
- Endangered
- Critically Endangered
- Extinct in the Wild
- Extinct
Least Concern
Not at risk of disappearing from the wild right now.
See the IUCN Red List assessment · The IUCN Red List of Threatened Species 2022.2
Amazing facts
-
A squirrel monkey's tail is longer than its body!
A squirrel monkey's tail can be up to 45 centimeters long, longer than its head and body.
Tail length (36 to 45 centimeters) exceeds head-and-body length (about 26.5 to 37 centimeters).
-
Boy squirrel monkeys get chubby before they look for a mate.
Before the mating season, male squirrel monkeys put on extra weight in their arms and shoulders, so they look puffed up.
Males gain about 85 to 222 grams before the mating season, mainly in the upper arms, shoulders and torso, giving a "fattened" look.
-
Squirrel monkeys listen to capuchin monkeys to stay safe.
Squirrel monkeys react more strongly to capuchin monkeys' warning calls than to their own.
In mixed groups, squirrel monkeys respond more strongly to capuchin predator alarms than to conspecific calls.
-
Boy squirrel monkeys cannot tell red from green.
All male squirrel monkeys are red-green colorblind, but some females see a full range of colors.
X-linked opsin genes make every male dichromatic, while heterozygous females are trichromatic.
Words to know
- insectivore
- an animal that eats mostly insects
- prehensile
- able to grab and hold, like some monkeys' tails
- colorblind
- unable to tell some colors apart, such as red and green
- introduced
- brought by people to a place where it did not live before
- pet trade
- catching and selling wild animals to keep as pets
Discovery challenge
-
What does a squirrel monkey use its long tail for?
How does a squirrel monkey use its long tail?
What is the main function of the squirrel monkey's non-prehensile tail?
- Balancing in the trees
- Grabbing branches like a hand
- Digging for food
Show the answer
Balancing in the trees
It helps the monkey balance. It cannot grab with it.
It holds the tail steady to balance; unlike many South American monkeys, it cannot grab with it.
The tail is held at a low angle as a balance aid; it is not prehensile.
-
What do squirrel monkeys eat when fruit is hard to find?
What do common squirrel monkeys mostly eat in the dry season?
Which food dominates the squirrel monkey's diet when fruit is scarce?
- Insects
- Grass
- Fish
Show the answer
Insects
They eat lots of bugs.
Insects: they even unroll dead leaves to find bugs hiding inside.
Insects, especially caterpillars and grasshoppers; squirrel monkeys are the most insectivorous Latin American primates.
-
Which monkeys do squirrel monkeys often follow?
Which bigger monkeys do squirrel monkeys often travel with?
With which primates do squirrel monkeys form beneficial associations?
- Capuchin monkeys
- Gorillas
- Baboons
Show the answer
Capuchin monkeys
They follow capuchins and pick up fruit they drop.
Capuchins: squirrel monkeys get dropped fruit and early warnings about predators.
Capuchins: the association gives squirrel monkeys access to dislodged fruit and capuchin alarm calls.
-
Where do wild common squirrel monkeys live?
Where is the wild home of the common squirrel monkey?
Where is Saimiri sciureus native?
- South America
- Africa
- Florida
Show the answer
South America
They live in South America. The ones in Florida were brought by people.
South America: the Guianas and northern Brazil. Squirrel monkeys in Florida were brought there by people.
The Guianas and northern Brazil; Florida groups are introduced, not native.
Places where you might see it
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Watch
Country
Suriname
Suriname is on the northern coast of South America, between Guyana and French Guiana. Rainforest covers the southern four-fifths of the land, home to jaguars, giant otters and harpy eagles. Its people have roots in India, Africa, Indonesia, China, Europe and the Americas, and Dutch is the official language.
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Watch
Country
Guyana
Guyana is on the northeastern coast of South America. Its name comes from an Indigenous word meaning land of water, and it fits: four big rivers cross it, and Kaieteur Falls plunges 226 meters in a single drop. Rainforest covers about three-fourths of the land. It is the only country in South America where English is the official language.
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Watch
Country
Brazil
Brazil covers about half of South America and is the fifth-largest country in the world. It holds most of the Amazon River basin and much of the world's largest rainforest, and about 214 million people lived there in 2026, most of them near the Atlantic coast.
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The white-faced capuchin is a smart, curious monkey from the forests of Central America, with black fur and a cream-white face, throat and shoulders. It eats fruit and hunts insects, lives in close family troops led by an alpha male, and on one island in Panama some capuchins crack open nuts and crabs with stones.
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The mantled howler is a big black monkey with a golden fringe of long hair on its sides, like a cape. Troops call to each other with deep, roaring howls at dawn and dusk. It lives in the rainforests of Central America and northwestern South America and eats mostly leaves and fruit.
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Country
Suriname
Suriname is on the northern coast of South America, between Guyana and French Guiana. Rainforest covers the southern four-fifths of the land, home to jaguars, giant otters and harpy eagles. Its people have roots in India, Africa, Indonesia, China, Europe and the Americas, and Dutch is the official language.
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Watch
Country
Guyana
Guyana is on the northeastern coast of South America. Its name comes from an Indigenous word meaning land of water, and it fits: four big rivers cross it, and Kaieteur Falls plunges 226 meters in a single drop. Rainforest covers about three-fourths of the land. It is the only country in South America where English is the official language.
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Watch
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Brazil
Brazil covers about half of South America and is the fifth-largest country in the world. It holds most of the Amazon River basin and much of the world's largest rainforest, and about 214 million people lived there in 2026, most of them near the Atlantic coast.
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Pygmy marmoset
The pygmy marmoset is one of the smallest monkeys in the world: an adult weighs about as much as a small apple. It lives in the riverside rainforests of the western Amazon, where it bites little holes in tree bark and licks up the sticky gum that oozes out. Families share the work of carrying the babies, which are usually twins.
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Aardvark
The aardvark is a shy night digger of African savannas. It sniffs out ant and termite nests, rips them open with its spade-like claws and laps up the insects with a sticky tongue about 30 centimeters long. Its name means 'earth pig' in Afrikaans.
For parents & teachers
What children will learn
- Describe how squirrel monkeys change their diet with the seasons.
- Explain the difference between a prehensile tail and a tail used for balance.
- Understand why scientists sometimes split one species into several.
- Discuss why wild monkeys should not be kept as pets.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- Why might it help a small monkey to travel with bigger capuchins?
- How could seeing fewer colors change the way a monkey finds fruit or insects?
- Why do you think people buy wild monkeys as pets, and why is that a problem?
Try at home or in class
- Walk carefully along a line on the floor while holding a broom handle out to one side, then without it: how does extra weight help you balance, the way a tail does?
- Find French Guiana, Suriname, Guyana and the Amazon River on a map of South America.
Key vocabulary: insectivore, prehensile, colorblind, introduced, pet trade
Where these facts come from
- GBIF Backbone Taxonomy and GBIF Occurrence Search , Global Biodiversity Information Facility (CC0 1.0 (backbone); occurrence counts are facts derived from records under CC0, CC BY and CC BY-NC)
- The IUCN Red List of Threatened Species , International Union for Conservation of Nature (IUCN terms of use (no redistribution of Red List data or range maps))
- Guianan squirrel monkey, Saimiri sciureus , New England Primate Conservancy
- Squirrel monkey (Saimiri) factsheet , Primate Info Net, Wisconsin National Primate Research Center
- Saimiri sciureus: IUCN Red List global assessment record (Silva Junior et al. 2021), IUCN checklist on GBIF , GBIF
- Saimiri sciureus (Guianan Squirrel Monkey), Silva Junior et al. 2021, global assessment , IUCN Red List of Threatened Species
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Wikimedia Commons , Wikimedia Foundation (Per file: Public domain, CC0, CC BY or CC BY-SA only (credited on each page))
Checked, not yet human-reviewed. Last updated November 1, 2026. Spotted a mistake? Tell us.