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." 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 on when the squirrel monkeys were released.In the 1960s, a colony of twelve to fifteen common squirrel monkeys was noted residing in a hammock of trees by the springs; they migrated downstream to the Ocklawaha River by 1975. Another population, derived from two pairs released in the 1960s, lives on the Bartlett Estate in Broward County; they numbered 43 in 1988. In 1976, 15 squirrel monkeys escaped from the Tropic Wonderland attraction in Titusville, Florida; their descendants have since become established in the area. In the 1980s, 500 and 1000 common squirrel monkeys remained in the shuttered Masterpiece Gardens park in Polk County, persisting despite efforts to capture them.