The black squirrel monkey (Saimiri vanzolinii), also known as the blackish squirrel monkey or black-headed squirrel monkey, is a small New World primate, endemic to the central Amazon in Brazil.[2] It largely resembles the female of the far more common Bolivian squirrel monkey, though the latter lacks the black central back.[4]
This squirrel monkey has one of the most restricted geographical distributions for a primate, living in várzea forest in the confluence of the Japura and Solimões rivers. Its entire range is within the Mamirauá Sustainable Development Reserve.[2] It resides in the reserve with two other Saimiri species.[5] It is a social primate that travels with other black squirrel monkeys in large troops within its habitat.[6] Its small size makes it an easy target for its predators; however, it may resist predators when it travels in large troops.[6]
Its species overall has positive effects on the economy.[7]
Black squirrel monkeys are small primates.[6] They have blackish-gray fur over most of their body except for their legs and stomach.[7] Their legs can be yellow or have a reddish tint.[7] Their stomachs will have a yellow tint.[6] They have short and dense fur everywhere except for certain areas on the face.[7] They lack hair in the areas of the nostrils and lips, and the skin is black in these areas.[7] Black squirrel monkeys tend to be 27 to 32 centimeters in length not including the length of their tails.[6] Their full length, including their tails, can be about 40 centimeters longer than their length without their tails.[7] Male black squirrel monkeys range in weight anywhere from 0.64 to 1.22 kilograms (1.4 to 2.7 pounds).[6] Female black squirrel monkeys have a weight range of 0.64 to 0.86 kg (1.4 to 1.9 lb).[6]
They get their name from the strip of black that extends from their head to the end of their tail.[8] The black fur above their eyes forms a shallow arch and is lower on their foreheads than other species.[8] Their tails are specifically distinct from the Saimiri sciureus species because black squirrel monkeys have much thinner tails.[8]
On average, black squirrel monkeys live up to 15 years in their natural habitat, the várzea forest.[6] They can live about 5 to 10 years longer than that when they are kept in captivity.[6]
The black squirrel monkey falls under the genus, Saimiri.[7] There are four other species that fall under this same genus with the black squirrel monkey.[8]
UCLA scientists and colleagues concluded that black squirrel monkeys are a distinct species of Saimiri when it was originally considered the same species as Saimiri boliviensis.[9]
Black squirrel monkeys reside within the Mamirauá Sustainable Development Reserve in Brazil.[6] The várzea forest of this specific area experiences a consistent cycle of flooding.[9] The patterns of rain can cause a typical buildup of around 35 feet of flooding in the forest.[9] Atypical flooding due to excessive floods over a longer amount of time can threaten black squirrel monkeys' habitat.[9]
Two species, Humboldt's squirrel monkey and Ecuadorian squirrel monkey, take residence in the reserve in cohabitation with black squirrel monkeys.[5] The black squirrel monkeys inhabit a smaller ranged area than the other two species within the reserve.[5] All three species interact with one another but sexual interaction and reproduction between two different species has not been observed.[5]
The black squirrel monkey species is declared endangered because of their limited range in the várzea forest.[6] The change in climate due to global warming is also affecting the lives of the black squirrel monkey species.[9]
They are interactive primates.[6] They exist in large groups of 40–50, and can exist in groups as large as 500 monkeys.[6] Travelling in big groups allows these monkeys to resist their predators more effectively.[6] They have more eyes on their surroundings which allows them to more easily and quickly alert the pack if they sense danger.[7] If the pack is big enough, the pack may be able to surround certain predators.[7]
Black squirrel monkeys are typically quiet primates.[7] The only times they make noise are when they sense danger or are trying to call out to other members of their group.[7]
Breeding season falls between the months of September and November.[7] During this season, the male monkeys with fattened stomachs are desired more by the female monkeys.[6] A female monkey's pregnancy will last about 140 to 170 days, and the time of birth falls at the same time that rainfall and food availability are at their peaks.[7]
The black squirrel monkey is preyed upon by snakes, raptors, and felids.[6]
This black squirrel monkeys is omnivorous.[7] It prefers fruit and insects, but also eats leaves, flowers, seeds, eggs, and small vertebrates.[6][7]
Black squirrel monkeys have a positive effect on the economy by serving as subjects of biomedical research, being sold to serve as an individual's pet, and serving as a source of food.[7] There are no negative impacts of the species on the economy because of the species' small habitation range that they occupy.[7]