The squirrel monkeys are the New World monkeys of the genus Saimiri. They are the only genus in the subfamily Saimirinae. The name of the genus Saimiri is of Tupi origin (sai-mirim or gai-mbirin < sai 'monkey' and mirim 'small'), and was also used as an English name by early researchers.Squirrel monkeys live in the tropical forests of Central and South America in the canopy layer. Most species have parapatric or allopatric ranges in the Amazon, while S.