Atelinae

a subfamily of platyrrine monkeys of the family Cebidae. The monkeys weigh between 4 and 10 kg. The body measures from 34 to 65 cm long, and the tail length is from 55 to 90 cm. The tip of the hairless underside of the tail is covered with cutaneous ridges. The arms are usually longer than the legs; in some individuals the arms and legs are almost equal in length. The thumbs are poorly developed or absent; only monkeys of the genus Lagothrix have thumbs. The big toe is developed. The fur is long and varies in coloration.

The subfamily Atelinae comprises three genera: Ateles (spider monkeys), with four species; Brachyteles (woolly spider monkeys), with one species; and Lagothrix, with two species. The monkeys are distributed in the forests of Central and South America. They live in trees and travel by semibrachiation, hanging by their arms and tails. The animals associate in small family groups or in troops of as many as 100 individuals. They feed on fruits, nuts, insects, and the eggs of birds.