- either of two small, long-tailed monkeys, Saimiri oerstedii of Central America and S. sciureus of South America, having a small white face with black muzzle and gold, brown, or greenish fur: S. oerstedii is endangered.
- a small New World monkey, Saimiri sciureus, of N South American forests, having a yellowish-green coat and orange feet and limbs
- a related species, Saimiri oerstedi, of Central America, having a reddish coat and dark brown limbs
