Saimiri vanzolinii 

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Cebidae

Scientific Name: Saimiri vanzolinii
Species Authority: Ayres, 1985
Common Name(s):
English Black-headed Squirrel Monkey, Black Squirrel Monkey
Taxonomic Notes: Saimiri taxonomy follows Hershkovitz (1984) and Groves (2001, 2005). An alternative taxonomy is presented by Thorington Jr. (1985) as follows: S. sciureus sciureus (includes the forms albigena, macrodon, and ustus recognized by Hershkovitz, [1984]), S. sciureus boliviensis (includes the forms pluvialis Lönnberg, 1940 and jaburuensis Lönnberg, 1940 recognized by Hershkovitz [1987]), S. sciureus cassiquiarensis, S. sciureus oerstedii (includes the form citrinellus recognized by Hershkovitz [1984]), and S. madeirae (given as a junior synonym of S. ustus by Hershkovitz [1984]). Hernández-Camacho and Defler (1989) recognize S. sciureus caquetensis Allen 1916, given as a junior synonym of S. sciureus macrodon by Hershkovitz (1984). Costello et al. (1993) argued for the recognition of just two species: S. sciureus in South America, and S. oerstedii in Panama and Costa Rica. Boinski and Cropp (1999) using two nuclear genes (IRBP and ZFX) and one mitochondrial (D-Loop) strongly support the Hershkovitz (1984) taxonomy, advocating four distinct species: Saimiri sciureus, S. boliviensis, S. oerstedii and S. ustus.

Hershkovitz (1987) referred to S. vanzolinii as a subspecies of S. boliviensis.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Boubli, J.-P. & Rylands, A.B.
Reviewer(s): Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
This species is listed as Vulnerable given that its entire range is confined to the Mamirauá State Sustainable Development Reserve, which although well managed and free of hunting, nonetheless is susceptible to selective logging, especially along the main stream of the Amazon.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species has a very small range circumscribed by the Rios Solimões and Japurá and the Auatí-Paraná (Ayres 1985).
Countries occurrence:
Brazil (Amazonas)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Common in a large part of its range. It has been recorded at a population density of 2.8 groups/km² (Ayres 1986).
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Typically prefers seasonally inundated forests, river edge forest, floodplain, and secondary forests. They use all levels of the forest, but forage and travel mainly in the lower canopy and understorey. Locomotion involves predominantly quadupredal walking and running.

Squirrel monkeys are small frugivore-insectivores. They spend 75-80% of their day foraging for insects and other small animal prey (Mittermeier and Van Roosmalen 1981; Terborgh 1983; Boinski 1988). During dry season shortages of appropriate fruiting trees they are able to depend entirely on animal prey (Janson and Boinski 1992).

Saimiri groups are multi-male and can be large, up to 100 animals (larger groups are believed to be temporary mergers of two) but most frequently are of 20-75 individuals (Baldwin and Baldwin 1981; Terborgh 1983; Mitchell et al. 1991). As emphasized by Boinski (1999a,b; 2005; Boinski et al. 2005a,b), allthough all squirrel monkeys are morphologicallly very similar, their social systems are quite distinct (summarized in Sussman 2000). However, there have been no studies of this species to date, and its ecology is inferred from those of other species. It is probable that its social orgnaization will be similar to that of S. boliviensis.

Mating and births in Saimiri are highly seasonal, seldom exceeding two months in duration. Single offspring. Mating usually occurs during the dry season. In S. oerstedii, sexual receptivity in females is synchronized, and lasts only or two days each season. In S. sciureus, birth synchrony is less pronounced and births occur only once every two years.

Amazonian Saimiri frequently form interspecific associations, travelling with Cebus albifrons or Cebus apella (Terborgh 1983; Wallace et al. 2000), benefitting from the disturbance casued by the capuchin monkeys above them which flushes out insects.

Size: Adult male 950 g; adult female 650 g (Jack 2007).

Threats [top]

Major Threat(s): The entire range of S. vanzolinii is within the Mamirauá State Sustainable Development Reserve (1,124,000 ha) (Rylands 1994). People are living within the reserve, but are permitted to use natural resources sustainably. The species is not known to be hunted. This species was formerly thought to be declining due to hybridization with S. s. cassiquiarensis, but this is uncertain.

Conservation Actions [top]

Conservation Actions: As noted, the species occurs entirely in the Mamirauá State Sustainable Development Reserve (1,124,000 ha) (Ayres 1984; Queiroz 1995). It is listed on CITES Appendix II.

Classifications [top]

1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
suitability:Suitable  major importance:Yes
1. Forest -> 1.8. Forest - Subtropical/Tropical Swamp
suitability:Suitable  major importance:Yes
4. Education & awareness -> 4.3. Awareness & communications

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
  Subject to recent education and awareness programmes:Yes
  Included in international legislation:Yes
  Subject to any international management/trade controls:Yes
2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.1. Shifting agriculture
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
3. Monitoring -> 3.1. Population trends

Bibliography [top]

Ayres, J. M. 1984. Estação Ecológica do Lago Mamirauá: Proposta para sua implantação. Relatório, Secretaria Especial do Meio Ambiente (SEMA), Brasília, DF.

Ayres, J. M. 1985. On a new species of squirrel monkey, genus Saimiri, from Brazilian Amazonia (Primates, Cebidae). Papéis Avulsos Zoologia, São Paulo 36: 147–164.

Baldwin, J. D. and Baldwin, J. I. 1981. The squirrel monkeys, genus Saimiri. In: A. F. Coimbra-Filho and R. A. Mittermeier (eds), The Ecology and Behavior of Neotropical Primates, pp. 277-330. Academia Brasileira de Ciências, Rio de Janiero, Brazil.

Boinski, S. 1988. Sex differences in the foraging behavior of squirrel monkeys in a seasonal habitat. Behavioural Ecology and Sociobiology 23: 177-186.

Boinski, S. 1999. Geographic variation in behavior of a primate taxon: stress responses as a proximate mechanism in the evolution of social behavior. In: S. A. Foster and J. A. Endler (eds), Geographic Variation in Behavior: Perspectives om Evolutionary Mechanisms, pp. 95-120. Oxford University Press, Oxford, UK.

Boinski, S. 1999. The social organization of the squirrel monkeys: implications for ecological models of social evolution. Evolutionary Anthropology 8: 101-112.

Boinski, S. and Cropp, S. J. 1999. Disparate data sets resolve squirrel monkey (Saimiri) taxonomy: Implications for behavioral ecology and biomedical usage. International Journal of Primatology 20(2): 237–256.

Boinski, S., Ehmke, E., Kauffman, L., Schet, S. and Vreedzaam, A. 2005. Dispersal patterns among three species of squirrel monkeys (Saimiri oerstedii, S. boliviensis and S. sciureus): II. Within-species and local variation. Behaviour 142(5): 633-677.

Boinski, S., Kauffman, L., Ehmke, E., Schet, S. and Vreedzaam, A. 2005a. Dispersal patterns among three species of squirrel monkeys (Saimiri oerstedii, S. boliviensis and S. sciureus): I. Divergent costs and benefits. Behaviour 142(5): 525-632.

Costello, R. K., Dickinson, C., Rosenberger, A. L., Boinski, S. and Szalay, F. S. 1993. Squirrel monkey (genus Saimiri) taxonomy: a multidisciplinary study of the biology of the species. Plenum Press, New York, USA.

de Queiroz, H.L. 1995. Preguiças e Guaribas: Os Mamíferos Folívoros Arborícolos do Mamirauá. Ministério de Ciência e Tecnologia (MCT) – CNPq. Sociedade Civil Mamirauá, Brasília e Tefé, Brazil.

Groves C. 2001. Primate Taxonomy. Smithsonian Institution Press, Washington, DC, USA.

Groves, C.P. 2005. Order Primates. In: D.E. Wilson and D.M. Reeder (eds), Mammal Species of the World, pp. 111-184. The Johns Hopkins University Press, Baltimore, Maryland, USA.

Hernández-Camacho, J. and Defler, T. R. 1989. Algunos aspectos de la conservación de primates no-humanos en Colombia. In: C. J. Saavedra, R. A. Mittermeier and I. B. Santos (eds), La Primatología en Latinoamerica, pp. 67-100. WWF-U.S., Washington, DC, USA.

Hershkovitz, P. 1984. Taxonomy of squirrel monkeys, genus Saimiri, (Cebidae, Platyrrhini): a preliminary report with description of a hitherto unnamed form. American Journal of Primatology 4: 209–243.

Hershkovitz, P. 1987. Uacaries, New World monkeys of the genus Cacajao (Cebidae, Platyrrhini): a preliminary taxonomic review with the description of a new subspecies. American Journal of primatology 12: 1–53.

IUCN. 2008. IUCN Red List of Threatened Species. Available at: (Accessed: 5 October 2008).

Jack, K. 2007. The cebines: toward an explanation of variable social structure. In: C. J. Campbell, A. Fuentes, K. C. Mackinnon, M. Panger and S. K. Bearder (eds), Primates in Perspective, pp. 107-123. Oxford University Press, Oxford, UK.

Mittermeier, R. A. and Van Roosmalen, M. G. M. 1981. Preliminary observations on habitat utilization and diet in eight Surinam monkeys. Folia Primatologica 36: 1–39.

Rylands, A. B. 1994. Macaco-de-cheiro, Saimiri vanzolinii Ayres, 1985. In: G. A. B. da Fonseca, A. B. Rylands, C. M. R. Costa, R. B. Machado and Y. L. R. Leite (eds), Livro Vermelho dos Mamíferos Brasileiros Ameaçados de Extinção, pp. 227-230. Fundação Biodiversitas, Belo Horizonte, Brazil.

Sussman, R. W. 2000. Primate Ecology and Social Structure, Vol. 2: New World Monkeys. Pearson Custom Publishing, Needham Heights, MA, USA.

Terborgh, J. 1983. Five New World Primates: A Study in Comparative Ecology. Princeton University Press, Princeton, NJ, USA.

Thorington Jr., R. W. 1985. The taxonomy and distribution of squirrel monkeys (Saimiri). In: L. A. Rosenblum and C. L. Coe (eds), Handbook of Squirrel Monkey Research, pp. 1–33. Plenum Press, New York, USA.

Wallace, R. B., Painter, R. L. E., Rumiz, D. I. and Taber, A. B. 2000. Primate diversity, distribution and relative abundances in the Rios Blanco y Negro Wildlife Reserve, Santa Cruz Department, Bolivia. Neotropical Primates 8(1): 24–28.

Citation: Boubli, J.-P. & Rylands, A.B. 2008. Saimiri vanzolinii. In: The IUCN Red List of Threatened Species 2008: e.T19839A9023022. . Downloaded on 20 January 2017.
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