Bolivian Squirrel Monkey


Bolivian Squirrel Monkey Fast Facts

  • Location: Bolivia, Brazil, Peru
  • Habitat: Lowland Tropical Rainforests
  • Lifespan: 15 Years
  • Diet: Fruit, Invertebrates , Seeds, Eggs, Small Mammals
  • Length: 22 - 37cm
  • Weight: 365 - 1135g


Black-capped squirrel monkeys are an arboreal species, found in the lowland forests of South America. They inhabit the canopies, particularly the small branches and occasionally, the forest floor. They are a very social species and can be found in groups ranging from 10 to 550 individuals. There is an established hierarchy of leadership within the group, always lead by a dominant female. They are known to be one of the most vocal species of squirrel monkeys, using different vocalisations to communicate to the group. The most common vocalisation used is a "chuck" noise, but they will also alert to dangers, shout in aggression, sound mating calls and paternal calls between mothers and offspring. Unlike other New World primates, their tail is not prehensile or used for climbing, Instead it acts as a balancing pole for stability when running along branches or standing on two-legs. Interestingly, baby squirrel monkeys are born with a prehensile tail, to assist with holding onto their parents, but lose this ability when they develop.



Black-capped squirrel monkeys are omnivores, eating both plants and animals. They will eat a variety of items including fruits, berries, seeds, tree gum, frogs, bats, spiders, eggs, and other small insects and animals. Because of their diet of fruits and seeds, this species acts as a seed disperser, assisting with the growth of the forest. Furthermore, they also help to control the insect populations, as one of their predators.



Squirrel monkeys breed only once per year, however this is dependent on seasonal influences. Females give birth during the rainy season, when food is most plentiful. After a 150- to 170-day gestation, females give birth to only one offspring. She is the sole provider, with the father's offering no assistance. Other females in the group will help raise the young, known as "aunting. Infants wean around 4 - 6 months old and become independent at around 1 year. Females reach sexual maturity at around 2.5-3 years of age. The males usually leave the main group once mature and form their own subgroup in the troop, consisting of immature males. When they reach 5 years old, they will join the mature male subgroup and are able to compete for dominance.


Threats + Conservation

Bolivian black-capped squirrel monkeys are listed as LEAST CONCERN on the IUCN Red List. Their main threat in the wild is habitat destruction due to agriculture, roads and logging. Sadly, this species is also hunted for food, the illegal pet trade and for use in medical research. Bolivian black-capped squirrel monkeys are part of the European Endangered Species Programme (EEP). This programme works to conserve healthy populations of animals in captivity while safeguarding the genetic health of the animals in captivity.


Fun facts

1. The black and white fur on their face gives them their German name, 'skull monkeys'. 2. Remarkably, the brain mass to body mass ratio for squirrel monkeys is 1:17, which gives them the largest brain, proportionately, of all the primates. 3. Baby squirrel monkeys are born with a prehensile tail, to assist with holding onto their parents, but lose this ability when they develop.


Bolivian Squirrel Monkey Gallery

Saimiri boliviensis


What shall we discover next?

Gidgee Skinks

Dwarf Zebu

Philippine Crocodile

Monkey Tailed Skink