Atelidae in the context of Cebidae

New World monkeys are the five families of primates that are found in the tropical regions of Mexico, Central and South America: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Ceboidea (/səˈbɔɪdi.ə/), the only extant superfamily in the parvorder Platyrrhini (/plætɪˈraɪnaɪ/).

Platyrrhini is derived from the Greek for "broad nosed", and their noses are flatter than those of other simians, with sideways-facing nostrils. Monkeys in the family Atelidae, such as the spider monkey, are the only primates to have prehensile tails. New World monkeys' closest relatives are the other simians, the Catarrhini ("down-nosed"), comprising Old World monkeys and apes. New World monkeys descend from African simians that colonized South America, a line that split off about 40 million years ago.

Spider monkeys are New World monkeys belonging to the genus Ateles, part of the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil. The genus consists of seven species, all of which are under threat; the brown spider monkey is critically endangered. They are also notable for their ability to be easily bred in captivity.

Disproportionately long limbs and long prehensile tails make them one of the largest New World monkeys and give rise to their common name. Spider monkeys live in the upper layers of the rainforest and forage in the high canopy, from 25 to 30 m (82 to 98 ft). They primarily eat fruits, but will also occasionally consume leaves, flowers, and insects. Due to their large size, spider monkeys require large tracts of moist evergreen forests, and prefer undisturbed primary rainforest. They are social animals and live in bands of up to 35 individuals, but will split up to forage during the day.

The Pitheciidae (/pɪθɪˈsaɪ.ɪdiː/) are one of the five families of New World monkeys now recognised. Formerly, they were included in the family Atelidae. The family includes the titis, saki monkeys and uakaris. Most species are native to the Amazon region of Brazil, with some being found from Colombia in the north to Bolivia in the south.

The Atelinae are a subfamily of New World monkeys in the family Atelidae, and includes the various spider and woolly monkeys. The primary distinguishing feature of the atelines is their long prehensile tails, which can support their entire body weight.

Atelines live on the American continent from southern Mexico through central Brazil and Bolivia. Diurnal and arboreal, they move speedily and acrobatically through the trees using their tails. Atelines, along with the related howler monkeys, are the largest of the New World monkeys. They live in groups, show amicable intergroup relations, and can coalesce into large aggregations for extended periods of time.

The woolly monkeys are the genus Lagothrix of New World monkeys, usually placed in the family Atelidae.

Both species in this genus originate from the rainforests of South America. They have prehensile tails and live in relatively large social groups.