Some species of Old World monkeys inhabit tropical rainforests, while others live on arid grasslands … Old World monkeys are unlike apes in that most have tails (the family name means ‘tailed ape’), and unlike the New World monkeys their tails are never prehensile. The prehensile tail is a characteristic feature that differentiates New World monkeys from the Old World monkeys. AnimalSake provides information and interesting facts about animals with prehensile tails. Many are small, arboreal and nocturnal, so our knowledge of them is less comprehensive than that of the more easily observed Old World monkeys. No other family of primates in either the New or the Old World has tails that are strong enough to function in this way as "third hands." Most New world monkeys have long, often prehensile tails. Unlike most Old World monkeys, many New World monkeys form monogamous pair bonds and show substantial paternal care of young. The family of New world monkeys called Callitricids (which are the marmosets and tamarins) DO NOT have prehensile tails. Some animals have prehensile tails. Many of the larger Cebidae have strong prehensile tails that are largely hairless on the underside and have sensitive tactile pads. HOWEVER all of the Cebids DO have prehensile tails. This adaptation is particularly helpful in allowing these animals to find and grab their prey or food.