There is no estimate on the number of monkeys in the world, but there are 260 known species of monkeys, which are divided into two categories: Old World and New World. Old World monkeys reside in Africa and Asia, and New World monkeys in South and Central America.
South and Central American monkeys possess prehensile tails and nostrils set widely apart. Old World monkeys are either tailless or have non-prehensile tails, and they possess rump pads, close-set nostrils and cheek pouches to store food. In New World animals, the pygmy marmoset is smallest, weighing 4.2 to 6.7 ounces, while the southern muriqui weighs between 26 and 33 pounds. The Old World mandrill is the largest monkey in the world at 77 pounds.