Monkeys are haplorhine (“dry-nosed”) primates, a paraphyletic amass for the most part having tails and comprising of around 260 known living species. Numerous monkey species are tree-abiding (arboreal), despite the fact that there are species that live essentially on the ground, for example, mandrills. Most species are additionally dynamic amid the day (diurnal). Monkeys are by and large thought to be clever, especially Old World monkeys.

Lemurs, lorises, and galagos are not monkeys; rather they are strepsirrhine (“wet-nosed”) primates. Like monkeys, tarsiers are haplorhine primates; in any case, they are likewise not monkeys. There are two noteworthy sorts of monkey: New World monkeys (platyrrhines) from South and Central America and Old World monkeys (catarrhines of the superfamily Cercopithecoidea) from Africa and Asia. Hominoid primates (gibbons, orangutans, gorillas, chimpanzees, and people), which all need tails, are likewise catarrhines however are not considered monkeys.