Saimiri ustus Saimiri sciureus 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. Habitat Black squirrel monkeys reside within the Mamirauá Sustainable Development Reserve in Brazil. The várzea forest of this specific area experiences a consistent cycle of flooding. The patterns of rain can cause a typical buildup of around 35 feet of flooding in the forest. Atypical flooding due to excessive floods over a longer amount of time can threaten black squirrel monkeys' habitat. Observations Two species, Humboldt's squirrel monkey and Ecuadorian squirrel monkey, take residence in the reserve in cohabitation with black squirrel monkeys. The black squirrel monkeys inhabit a smaller ranged area than the other two species within the reserve. All three species interact with one another but sexual interaction and reproduction between two different species has not been observed. Vulnerability The black squirrel monkey species is declared endangered because of their limited range in the várzea forest. The change in climate due to global warming is also affecting the lives of the black squirrel monkey species. Behaviour They are interactive primates. They exist in large groups of 40–50, and can exist in groups as large as 500 monkeys. Travelling in big groups allows these monkeys to resist their predators more effectively. They have more eyes on their surroundings which allows them to more easily and quickly alert the pack if they sense danger. If the pack is big enough, the pack may be able to surround certain predators. Communication Black squirrel monkeys are typically quiet primates. The only times they make noise are when they sense danger or are trying to call out to other members of their group. Reproduction Breeding season falls between the months of September and November. During this season, the male monkeys with fattened stomachs are desired more by the female monkeys. 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. Ecological role The black squirrel monkey is preyed upon by snakes, raptors, and felids. This black squirrel monkeys is omnivorous. It prefers fruit and insects, but also eats leaves, flowers, seeds, eggs, and small vertebrates. Economic importance Black squirrel monkeys have a positive effect on the economy by serving as subjects of biomedical