Common squirrel monkey is the traditional common name for several small squirrel monkey species native to the tropical areas of South America. The term common squirrel monkey had been used as the common name for Saimiri sciureus before genetic research by Jessica Lynch Alfaro and others indicated S. scuireus covered at least 3 and possibly 4 species: the Guianan squirrel monkey (S. scuireus), Humboldt's squirrel monkey (S. cassiquiarensis) and Collins' squirrel monkey (S. collinsi). The Ecuadorian squirrel monkey (S. cassiquiarensis macrodon), generally regarded as a subspecies of Humboldt's squirrel monkey, had also been sometimes proposed as a separate species that had originally been included within the term "common squirrel monkey." Range and introductions Common squirrel monkeys are found primarily in the Amazon Basin. Before the taxon was split, it had been considered to be found within the countries of Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela; a small population has been introduced to Florida and many of the Caribbean Islands. However, taxonomic research in 2009 and 2015 determined that several populations that had been considered S. scuireus were actually separate species: Guianan squirrel monkey, S. sciureus Collins' squirrel monkey, S. collinsi Humboldt's squirrel monkey, S. cassiquiarensis The Ecuadorian squirrel monkey, S. cassiquiarensis macrodon, has also sometimes been regarded as a separate species. As a result of these populations no longer being considered S. scuireus, the range of S. scuireus is now limited to Brazil and the Guianas. A group of free-ranging individuals was spotted and photographed in 2009 at the Tijuca Forest in Rio de Janeiro – possibly the result of an illegal release or of an escape from the pet trade; by 2010, the squirrel monkey had begun to be considered as an invasive species in the Brazilian Atlantic rainforest, and concerns were expressed about its role as a predator of eggs of endangered bird species. The common squirrel monkey prefers to live in the middle canopy, but occasionally comes to the ground or goes up into the high canopy. They like vegetation which provides good cover from birds of prey in the rainforest, savannah, mangroves, or marshlands. At least five populations of common squirrel monkeys have existed in Florida since the 1960s, if not earlier. Common squirrel monkeys have been established at Silver Springs since at least the late 1960s; rhesus macaques were established in the area by 1938, but there is no firm information