To help them balance and control their movement as they leap from branch to branch. The tails of some South American monkeys are like a fifth limb, with special muscles which help them to tightly grip branches.
A few isolated monkey species do not have tails either, but they are the exception rather than the rule. Old World monkeys are most quickly differentiated from New World monkeys by looking at their tails.
The Old World monkeys have non-prehensile tails that can not grip. The New World monkeys have long slim prehensile tails that they may climb with and that they can carry and manipulate items with.
The most dexterous tail in the monkey kingdom belongs to the spider monkey. These monkeys can hold, carry and even catch items with their tails, and will gesture with them as well.
There is a small bare area of rough skin on the underside of the last vertebra in the tail. This “tactile pad” has many nerve endings like a fingertip, which aids in delicate tasks like peeling a banana.
The prehensile tail is surely a product of the New World monkeys densely forested environment. Most New World monkeys are largely arboreal, spending the majority of their time high in the forest canopy, and some never leave the trees at all. While many Old World monkeys like the baboons, spend most of their time on the ground walking around on all fours like a dog.
Credit : Animal Facts Encyclopedia
Picture Credit : Google
