Any of several small, brightly colored arboreal monkeys of the genus Saimiri, widely distributed in South and Central American tropical forest regions, having a white face with black nose and mouth, short fur, and a long nonprehensile tail. Any of several species (genus Saimiri, family Cebidae) of arboreal New World monkeys, found in groups of up to several hundred during the day in riverside forests of Central and South America. They eat fruit, insects, and small animals. They are 10-16 in. (25-40 cm) long and have a heavy, nonprehensile, black-tipped tail, 15-19 in. (37-47 cm) long. They have a small white face, large eyes, and large, usually tufted, ears. The short, soft coat is grayish to greenish, with yellow or orange arms, hands, and feet. The crown of the common squirrel monkey (S. sciureus) is olive or grayish; the red-backed squirrel monkey (S. oerstedii) has a black crown and reddish back