Black-Capped Squirrel Monkey Fact File


The black-capped squirrel monkey is a small monkey which is covered by a coat of dense, short yellowish fur. Their name comes from the dark crown on top of the head. This is colored black in females and gray in males. The underside of the limbs is colored yellow, orange or white.

Around the eyes and cheeks the fur is white. On the ears are tufts of white fur.

At the end of the body is a long tail which is longer than the head and body combined. This measures between 38 and 42cm (15-16.5in) long. At its tip the tail expands and is colored black. This tail is not prehensile in adults but juveniles do have this ability.

Males are larger than females. An average squirrel monkey will measure between 27 and 32cm (10.5-12.5in) long. Males weigh in at 1kg (2.2lbs) while females weight in at 0.8kg (1.8lbs).


Black capped squirrel monkeys are omnivores. They feed on a range of fruit, seeds, insects and small animal prey.

During the dry season they may have a shortage of fruit and during this time they can depend entirely on animal prey.

When one member of the group finds food the rest of the group will join them to feed.

black capped squirrel monkey

Scientific Name

Saimiri boliviensis

Conservation Status

Least Concern



1kg (2.2lbs)


0.8kg (1.8lbs)


27-32cm (10.5-12.5in)


15-20 years



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South America is the native home of the black-capped squirrel monkey. Here they can be found in Bolivia, Brazil and Peru.


These animals can be found in river edge forests, seasonally inundated forests, floodplains and secondary forests.

black-capped squirrel monkey


Black-capped squirrel monkeys will breed during a three month period each year. All females in the troop synchronize their estrus.

Throughout the breeding season both males and females will mate with multiple partners each season. Males will fight one another to increase their dominance and as such access to females.

Outside of the breeding season males live on the periphery of the group on their own. They are only allowed to join the main group for the breeding season.

Prior to the breeding season the male gains considerable amounts of weight which helps to increase sperm production.

Often a female will help to care for the infants of other members of her troop.

The mother will give birth to a single infant after a gestation period of between 152 and 172 days. Mothers are highly protective of their offspring.

An infant will suckle milk from its mother for 4 to 6 months before weaning.

Females remain in the group which they were born in for life while the males will move out of their group between 4 and 5 years old.

Sexual maturity is reached between 2 and 3 years old for females while sexual maturity is reached at 5 years old for males.


Squirrel monkeys form some of the largest troops of any monkey species. These are formed with an average of 40-50 members though sometimes as many as 100 are part of the group.

Groups larger than 100 have been recorded but it is believed that these are temporary mergers of more than one group.

Often groups of black-capped squirrel monkeys will travel with groups of capuchin monkeys. These larger monkeys flush out insects and small animals as they move around which the squirrel monkeys can then feed on.

These monkeys are highly vocal. While moving through the trees they will cluck and twitter.

Black-capped squirrel monkeys are arboreal. They will move through the forest easily jumping between branches. It is rare for them to go to the ground.

They are active during the day.

Males will urine-wash. This involves rubbing urine on their hands, feet and body so it leaves a trace when they move around.

black-capped squirrel monkey

Predators and Threats

Recorded predators of the black-capped squirrel monkey are humans and harpy eagles.

Black-capped squirrel monkeys are threatened through hunting especially in areas from which larger primates have been removed through hunting.

Habitat loss is another threat, as is capture for pets and medical research.

Quick facts

These monkeys may also be called the black-headed squirrel monkey or Bolivian squirrel monkey.

black-capped squirrel monkey

Photo Credits

Copyright. The Animal Facts.


Burnie, D., 2011. Animal. 3rd ed. London: DK

Heymann, E.W., Calouro, A.M., Vermeer, J., Mollinedo, J.M., Silva Júnior, J.S., Shanee, S., Rumiz, D.I., Muniz, C.C., Mittermeier, R.A. & Lynch Alfaro, J.W. 2021. Saimiri boliviensis (amended version of 2018 assessment). The IUCN Red List of Threatened Species 2021: e.T41536A192584127. Downloaded on 06 April 2021.

PerthZooWebsite. 2021. Bolivian Squirrel Monkey. [online] Available at: <> [Accessed 7 April 2021].

Buffalo Zoo. 2021. Black-Capped Squirrel Monkey - Buffalo Zoo. [online] Available at: <> [Accessed 7 April 2021]. 2021. Black-capped squirrel monkey. [online] Available at: <> [Accessed 7 April 2021].

Sipahi, L. 2006. "Saimiri boliviensis" (On-line), Animal Diversity Web. Accessed April 06, 2021 at

Covert, T., 2021. Black-capped squirrel monkey. [online] New England Primate Conservancy. Available at: <> [Accessed 7 April 2021].

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