New World Monkeys
New world monkeys live in the rainforests of South America, Mexico and Central America. These monkeys fall into two families: the Cebida and the Callitricida. The Callitricidae family consists of marmosets and tamarins, of which none have prehensile tails. The Cebida family, however, is divided into four different sub families called the Cebinae, Aotinea, Atelinae and Pithecinae. Most of the larger monkeys falling into the Cebida family have prehensile tails. Some of the individual species with prehensile tails include spider monkeys, howler monkeys, wholly monkeys and squirrel monkeys.
Old World Monkeys
Old world monkeys live in a variety of habitats in South and East Asia, the Middle East, Africa and Spain. There are 78 species of old world monkeys, divided into two families: the Cercopithecinae and Colobinae. The monkeys in both families are large, comparable in size to small- to medium-size dogs. Most monkeys fall into the family Cercopithecinae and include such species as baboons, pata monkeys, macaques and mangabeys. The Colobinae include legurs and proboscis monkeys. None of the old world monkeys, however, have prehensile tails.
Predominant in South America
Most of the new world monkeys with prehensile tails live in the dense jungles of South America. Furthermore, not only do most monkeys with prehensile tails live in the South American rainforests, but most other mammals with prehensile tails live there are well. This observation has led most scientists and primatologists to conclude that the adaption evolved as a primary means to navigate the dense rain forest. In contrast, gliding monkeys are more predominant in Africa and Asia, where the rain forests are not as dense. Scientist also think this is because in South America there are many climbing mammals, making it hard to glide from one place to another.
Uses of a Prehensile Tail
The characteristics of a prehensile tail include a bare patch of skin on the tail to aid in gripping and powerful muscles useful for manipulating objects. The bare patch of skin, referred to as a "friction pad," makes it easier for the monkey to manipulate various objects. Because of this grip, many prehensile monkeys use their tails to hang onto branches so they can reach out and grab fruits and nuts with their hands. This greatly increases the monkeys' feeding sphere. Prehensile tails are also used to carry things, as an aid in climbing trees and to help monkeys escape from predators.