The monkeys' adaptations vary by their species and their natural habitat. One distinguishable adaptation of New World monkeys from Old World monkeys is the presence of a prehensile tail. Most prehensile tails are longer than a monkey's body, enabling him to swing from tree to tree effortlessly.
The arboreal lives of New World monkeys involve staying on top of the trees high up in the rain forest canopy. Spider monkeys have hook-like hands that allow them to hang and swing by their arms on tree branches, while their webbed toes enable them to swim and paddle through water to get food or escape predators. Spider monkeys and other herbivorous monkeys stay and rest on trees most of the time to digest the vast amount of leaves they consume everyday.
Some Old World monkeys, such as baboons and macaques, have cheek pouches that they use to temporarily secure and store their food. The pouches are useful since these omnivorous monkeys live in large groups, and they often need to compete for desirable food. Arboreal New World monkeys, however, lack cheek pouches, as they thrive on leaves, fruits and other plant materials.
Monkeys, especially the New World species, are very vocal. They have a highly developed larynx, enabling them to produce a wide range of sounds, such as bird-like calls and guttural sounds. These sounds allow them to send their message and communicate with their kind.