Saimiri boliviensis (I. Geoffroy and Blainville, 1834), Guarayos Mission, Rio San Miguel, Santa Cruz, Bolivia. Four subspecies. Elevated from subspecies of Saimiri sciureus in 1984.
OTHER COMMON NAMES English: Black-headed squirrel monkey.
Fur is sexually dichromatic—males gray and females black. Yellow at base of crown, on forearms, hands, and feet. Roman (rounded) arch over eyes. Head and body length is 12.2 in (31 cm). Tail length is 14.2 in (36 cm). Weight is 24.7-38.4 oz (700-1,088 g).
Brazil, Bolivia, Colombia, Peru, and Venezuela. HABITAT
Primary and secondary tropical rainforest.
Diurnal and arboreal. Multimale-multifemale groups of 20-50 animals. During breeding season males form hierarchy, and are dominant over females. For the rest of the year males are peripheral and subordinate to the females. Both males and females use genital display towards conspecifics. Female social aggression is common.
Predominately eat fruits, seeds, and animal prey including frogs, snails, insects, and spiders. Fruit is eaten earlier in the day, with animal protein eaten later.
Promiscuous mating. Males become "fatted" with upper body weight gain, an increase in testes size, and active spermatogen-esis just prior to the breeding season. Males compete with each other for dominance during the breeding season. Breeding season is followed six months later by a birth season (coinciding with the wet season) when food is most abundant. Females reach sexual maturity at 36 months and gestation is 155-170 days. Births are single.
Widespread and uncommon to locally common. Main pressures on populations include habitat degradation, deforestation, hunting for food, and collection for laboratories. Listed in Appendix 2 of CITES.
SIGNIFICANCE TO HUMANS
Hunted for food in those areas of range where larger mammals have been depleted. Collected for pet, zoo, and research market. ♦
H Saimiri oerstedii H Saimiri boliviensis
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