Monkey

A monkey is a nonhuman primate mammal with the exception usually of the lemurs and tarsiers. More specifically, the term monkey refers to a subset of monkeys: any of the smaller longer-tailed catarrhine or platyrrhine primates as contrasted with the apes.

Monkeys are broadly sudivided into the New World monkeys and Old World monkeys, two of the three groupings of simian primates (the third group being the apes). There are 264 known extant species of monkey.

The New World monkeys are classified within the parvorder Platyrrhini, whereas the Old World monkeys (superfamily Cercopithecoidea) form part of the parvorder Catarrhini, which also includes the apes. Thus, scientifically speaking, monkeys are paraphyletic (not a single coherent group), and Old World monkeys are actually more closely related to the apes than they are to the New World monkeys.

Due to its size (up to 1 m/3 ft) the Mandrill is often thought to be an ape, but it is actually an Old World monkey. Also, a few monkey species have the word "ape" in their common name.