Taken on 08/10/10 in Singapore Zoo
A monkey is any cercopithecoid (Old World monkey) or platyrrhine (New World monkey) primate. All primates that are not prosimians or apes are monkeys. The 264 known extant monkey species represent two of the three groupings of simian primates (the third group being the 22 species of apes). Monkeys are generally considered to be intelligent and, unlike apes, monkeys usually have tails.