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Squirrel monkey


CITES: Appendix II, Appendix I (S. oerstedti only) (What is CITES?)
IUCN Red List: S. oerstedti, S. vanzolinii: VU; S. ustus: NT; S. boliviensis, S. sciureus: LC (What is Red List?)
Key: VU = Vulnerable, VU = Vulnerable, NT = Near threatened, LC = Least concern, LC = Least concern
(Click on species name to see IUCN Red List entry, including detailed status assessment information.)

Saimiri sciureus
Saimiri sciureus
Photo: Luiz Claudio Marigo

Once thought to exceed 20,000 in number, S. oerstedti is facing serious conservation concerns in Central America. The estimated population of the Panamanian S. o. oerstedti is 2000 individuals while only 1500 S. o. citrinellus are thought to remain (Cropp & Boinski 2000). Unfortunately, there are no population estimates for S. vanzolinii and little published information about its conservation issues and future viability.


Threat: Human-Induced Habitat Loss and Degradation

In Costa Rica, squirrel monkeys are threatened because of increased rates and amounts of deforestation and forest fragmentation and infrastructure for the country's booming tourism industry. In Panama, they have fared even worse as deforestation has been rampant and virtually unregulated (Boinski & Sirot 1997; Boinski et al. 1998). The development of agribusinesses for oil palm and banana plantations is a serious component of habitat destruction and fragmentation. Squirrel monkeys rarely come to the ground, travel primarily on branches between one and two centimeters in diameter, and will not leap horizontally between trees if the distance is greater than two meters. Logging roads, clearings for telephone and electric power lines, or other practices leading to forest fragmentation restrict populations to smaller areas of forest, decreasing their ability to find food during times of year when food abundance is lowest and leading to a host of genetic diversity issues that could affect their conservation (Boinski et al. 1998).

Fortunately, Costa Rica exhibits among the highest conservation sophistication and largest proportion of protected lands in Central and South America; squirrel monkeys are protected at two reserves, Corcovado and Manuel Antonio National Parks (Cropp & Boinski 2000). Ironically, in protected parks where disturbance such as selective logging, clearing for swidden agriculture, and other sustainable disturbance regimes are prohibited, successional growth of secondary forests has resulted in an abundance of primary forest. This is specifically problematic for squirrel monkeys because they prefer secondary growth forests and will not use primary forests because of the low abundance of arthropods, fruits, and flowers compared to disturbed forests (Boinski et al. 1998).

Potential Solutions

Ecotourism in Costa Rica is focused on the unique fauna and flora of the country and is the largest source of foreign currency revenues (Boinski et al. 1998). Tourism proprietors should be enlisted to assist in conservation strategies revolving around squirrel monkeys in their areas, specifically to develop their operations responsibly with minimal habitat fragmentation.

In protected areas, management should be a focus of the Costa Rican government. In a pristine forest, natural disturbances such as hurricanes and floods would initiate the secondary forest regeneration process. When these types of habitats are not available, in an intact forest, squirrel monkeys would move to another adjacent area that may have secondary forest. Maintaining some areas of secondary successional growth within protected areas, or even better, protecting more adjacent lands surrounding Corcovado and Manuel Antonio would provide more suitable habitat for squirrel monkeys in these areas (Boinski et al. 1998).

Threat: Harvesting (hunting/gathering)

Squirrel monkeys are subject to capture and sale as pets in both domestic and foreign markets. One study revealed that in addition to being easy to obtain and frequently smuggled out of the countries of origin, squirrel monkeys are sold for an alarmingly low price, US$30-50 (Boinski et al. 1998).

Potential Solutions

The trade in squirrel monkeys could potentially be decreased through education programs and alternative income opportunities. Since ecotourism in Costa Rica centers on the unique animal and plant resources in the country, preserving these resources should be a priority to all those who benefit economically from tourism profits. Encouraging tourism operations to staff their outfits with local people will increase the sense of ownership for local populations and will give them direct economic benefit from preserving squirrel monkeys.

Threat: Accidental Mortality

One artifact of development of infrastructure for tourism includes power lines, for both electricity and telephone service. The leading cause of accidental mortality among squirrel monkeys is electrocution as they use power lines to move between patches of forest fragments (Boinski et al. 1998).

Potential Solutions

Better insulation on power lines would decrease the number of accidental deaths by electrocution, but another consideration is that squirrel monkeys use power lines to move between forested areas where natural corridors are not available. In addition to better insulation, maintaining branches that hang over roads and allowing the monkeys to use these to move across roads would increase mobility between fragments as would maintenance of brushy areas below power lines (Boinski et al. 1998).

Threat: Persecution

Where they exist near human settlements practicing small-scale agriculture, squirrel monkeys are occasionally hunted as pests because they often raid and destroy fruit crops, but this persecution is not nearly as serious as other threats facing squirrel monkeys (Boinski et al. 1998).

Potential Solutions

Landowner education about the extreme rarity of these squirrel monkeys might begin to change attitudes towards them and their crop-raiding behaviors, though no work has been done to decrease hunting of squirrel monkeys in this area.

Threat: Pollution

There is little direct evidence of squirrel monkey mortality from pollution, but in forests neighboring oil palm and banana plantations, where pesticides are used liberally, poisoning of squirrel monkeys could potentially be a serious threat to small populations. There have been reports of golden lion tamarins (Leontopithecus rosalia) that died after ingesting insects contaminated with pesticides (Pissinatti et al. 2002).

Threat: Natural Disasters

While hurricanes cause natural disturbances to primary forest that create the secondary growth forest preferred by squirrel monkeys, the hurricane itself can inflict great direct damage to the monkeys. In 1999 a hurricane was likely the responsible for the death of two-thirds of the main troop in Manuel Antonio National Park (Boinski & Sirot 1997).

Threat: Changes in Native Species Dynamics

Nocturnal predation in protected areas with intact predator populations may have an effect on squirrel monkeys. To minimize the chance of predation, squirrel monkeys sleep at the edges of palm fronds and in the case of disturbance, drop to the ground (Boinski & Sirot 1997). By sleeping at the edge of the branches, they decrease the number of predators that can reach them; palm fronds cannot support much weight, so any predator attempting to reach a sleeping squirrel monkey will likely cause disruption and the monkeys will drop to the ground and avoid predation.

Potential Solutions

Wildlife managers could supplement squirrel monkey habitat with sleeping sites that are predator-resistant to decrease the chance of predation and maintain the stability of squirrel monkey populations in some areas (Boinski & Sirot 1997).

Threat: Intrinsic Factors

The limited dispersal options for young, sexually maturing females may have effects on the viability of offspring born to closely related relatives. If females are restricted from emigrating because their natal group is in a forest fragment, the only option is to breed with males that are potentially their relatives (Boinski & Sirot 1997). Inbreeding can lead to a host of problems including inbreeding depression, genetic drift, and low levels of genetic diversity that are potentially serious threats to small populations of squirrel monkeys.

Potential Solutions

It should be a priority to maintain secondary growth forests in protected areas where squirrel monkeys are found in addition to increasing protected areas so that forests are more contiguous rather than fragmented. Corridors connecting habitat fragments may help dispersing females find new groups into which they can assimilate and mate.

Threat: Human Disturbance

One of the serious concerns about S. oerstedti conservation is the hesitancy of officials, especially in Costa Rica, to direct funding towards conservation initiatives because of the common belief that it is an introduced species to the area (Boinski et al. 1998; Cropp & Boinski 2000). With so few funds and a serious conservation crisis in this hotspot of biodiversity, it is politically unpopular to attempt gallant conservation efforts on a species thought to have been introduced by humans before the arrival of European settlers. This is particularly unfortunate because molecular genetic evidence proves the species distinction between S. oerstedti and other squirrel monkeys, and the population of both subspecies is dwindling to critically low numbers (Cropp & Boinski 2000).

Potential Solutions

Changing public attitudes towards squirrel monkeys in Costa Rica will likely engender specialized efforts to conserve this endemic resource. With additional data becoming available to prove their status as non-introduced species, perhaps the process of changing attitudes will quicken and focused conservation activities will become more of a priority for the Costa Rican government and non-governmental organizations.


Captive breeding programs of S. oerstedti are nonexistent in the United States. There are two breeding colonies in Costa Rica that have been maintained through animals seized in the pet trade, but as of 1997, there were only three individuals kept at the Phoenix Zoo (Boinski & Sirot 1997). While other species of squirrel monkeys are well represented in the captive population, problems with hybridization occur because of the changing taxonomic status and inattention to subspecific variation. Furthermore, the founder animals which started the breeding colonies may have been misclassified, making it impossible to differentiate between the species-type of current populations (Schreiber et al. 1998). The taxonomic categorization of captive populations of squirrel monkeys is confusing and not likely to be resolved without genetic testing; nonetheless, animals of questionable taxonomic status can be used in displays at zoos and for educational purposes, regardless of their pedigree.





Content last modified: March 16, 2006

Written by Kristina Cawthon Lang. Reviewed by Laurie Kauffman.

Cite this page as:
Cawthon Lang KA. 2006 March 16. Primate Factsheets: Squirrel monkey (Saimiri) Conservation . <>. Accessed 2019 September 18.