A prehensile tail is an adaptive trait found in many arboreal mammals and has evolved across a diverse group of species. Often associated with monkeys, the prehensile tail is a characteristic of some New World and no Old World species. A possible adaptation to life in a dense thicket of lianas that is absent throughout the Old World forests, New World monkeys use their tails as an appendage to navigate and suspend themselves from the trees. Interestingly, it is possible that the prehensile tail has evolved at least twice in New World monkey species. Howler, spider and woolly monkeys belonging to the family Atelidae have a true prehensile tail, while the capuchins in the family Cebidae are the only species to have a prehensile tail. While squirrel monkeys, marmosets and tamarins share the family Cebidae with the capuchins, the later is the only group in the family to have a degree dexterity with their tail.