monkey, any of a large and varied group of mammals of the primate order. The term monkey includes all primates that do not belong to the categories human, ape, or prosimian; however, monkeys do have certain common features. All are excellent climbers, and most are primarily arboreal. Nearly all live in tropical or subtropical climates. Unlike most of the prosimians, or lower primates, they are almost all day-active animals. Their faces are usually flat and rather human in appearance, their eyes point forward, and they have stereoscopic color vision. Their hands and feet are highly developed for grasping; the big toes and, where present, the thumbs are opposable. Nearly all have flat nails. Monkeys habitually sit in an erect posture. Unlike the apes, most cannot swing arm-over-arm (the spider monkey is an exception) but move about in trees by running along the branches on all fours; their skeletal structure is similar to that of other four-footed animals. Monkeys live in troops of up to several hundred individuals and travel about in search of food, having no permanent shelter. As in apes and humans, the female has a monthly reproductive cycle, and mating may occur at any time, but in some species mating is seasonal. Usually only one infant is born at a time; it is cared for by the mother for a long period. There are two large groups, or superfamilies, of monkeys: Old World monkeys (Cercopithecoidea) and New World monkeys (Ceboidea).
Old World Monkeys
The Old World monkeys are found in S Asia, with a few species as far N as Japan and N China, and in all of Africa except the deserts. Most are arboreal, but a few, such as baboons and some macaque species, are ground dwellers. Some Old World monkeys lack tails; when a tail is present it may be long or short but is never prehensile (grasping). The nostrils are close together and tend to point downward. Many species have cheek pouches for holding food, and many have thick pads (called ischial callosities), on the buttocks. Their gestation period is five to nine months. Adult Old World monkeys have 32 teeth. The Old World monkeys, sometimes called true monkeys, are more closely related to the apes and humans than they are to the New World monkeys; the two monkey groups probably evolved separately from ancestral primates.
The Old World monkeys include the many species of macaque, widely distributed throughout Africa and Asia. The rhesus monkey, commonly used in laboratory experiments, is an Asian macaque. Related to the macaques are the baboons of Africa and SW Asia, as well as the mandrill and mangabey of Africa. The guerezas, or colobus monkeys (genus Colobus), are very large, long-tailed, leaf-eating African monkeys. Their Asian relatives, the langurs and leaf monkeys, include the sacred monkeys of India. The snub-nosed monkey of China and the proboscis monkey of Borneo are langurlike monkeys with peculiar snouts. The guenons (Cercopithecus) are a large group of long-legged, long-tailed, omnivorous monkeys found throughout sub-Saharan Africa. One very widespread guenon species is the green monkey, or vervet, with olive-brown fur.
New World Monkeys
The New World monkeys are found from S Mexico to central South America, except in the high mountains, and are classified into two families (Callatrichids and Cebids). The Callatrichids are very small, while the Cebids are similar in size to the Old World monkeys. They are all thoroughly arboreal and most have long, prehensile tails with which they can manipulate objects and hang from branches. In most the thumb is lacking. They have widely separated nostrils that tend to point outward; they lack cheek pouches and ischial callosities. Their gestation period is four to five months. Adults of most New World species have 36 teeth.
The New World monkeys include the marmosets and tamarins, small monkeys with claws that are classified in a family of their own, the Callithricidae. The rest of the New World monkeys are classified in the family Cebidae. They include the capuchin (genus Cebus), commonly seen in captivity, which has a partially prehensile tail. Prehensile tails are found in the spider monkey and woolly monkey as well as in the howler monkey, the largest member of the family, which has a voice that carries several miles. Smaller forms with nonprehensile tails are the squirrel monkey and titi, the nocturnal douroucouli, or owl monkey, the saki, and the ouakari.
Monkeys are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Primates, superfamilies Cercopithecoidea and Ceboidea.
mon·key / ˈməngkē/ • n. (pl. -eys) 1. a small to medium-sized primate that typically has a long tail, most kinds of which live in trees in tropical countries. The New World monkeys (families Cebidae and Callitrichidae, or Callithricidae) have prehensile tails; the Old World monkeys (family Cercopithecidae) do not. ∎ (in general use) any primate. ∎ a mischievous person, esp. a child: you little monkey! ∎ fig. a person who is dominated or controlled by another (with reference to the monkey traditionally kept by an organ grinder). 2. a pile-driving machine consisting of a heavy hammer or ram working vertically in a groove. • v. (-eys, -eyed) [intr.] (monkey around/about) behave in a silly or playful way. ∎ (monkey with) tamper with. ∎ [tr.] archaic ape; mimic. PHRASES: make a monkey of (or out of) someone humiliate someone by making them appear ridiculous. a monkey on one's back inf. a burdensome problem. ∎ a dependence on drugs.
The monkey is a member of the order Primates. Like humans, monkeys can see in depth and in color and can grasp objects with hands and feet. They usually eat leaves, insects, fruits, and bird eggs.
New World monkeys, found from Mexico to South America, are smaller and lighter than Old World monkeys and have flat noses. The family Cebidae generally has a rounded head and thirty-six teeth. The legs are longer than the arms, and the limbs end in five digits. The family Callitrichidae are the New World's smallest monkeys. They have small, round heads and thirty-two teeth. The tail is longer than the head and body together.
Most species of the marmoset and tamarin families are threatened with extinction, due mainly to loss of habitat. Especially threatened are the golden lion tamarins of Brazil (Leontopithecus rosalia), fewer than five hundred of which are estimated to live in the wild.
Baschieri Salvatori, Francesco. Rare Animals of the World. New York: Mallard Press, 1990.
Boitani, Luigi, and Stefania Bartoli. Simon and Schuster's Guide to Mammals, trans. Simon Pleasance, pp. 95-105. New York: Simon and Schuster, 1983.
Patzelt, Erwin. Fauna del Ecuador. Quito: Banco Central del Ecuador, 1989.
Kay, Richard F., Blythe A. Williams, and Federico Anaya. "The Adaptations of Branisella boliviana, the Earliest South American Monkey." In Reconstructing Behavior in the Primate Fossil Record, ed. J. Michael Plavcan et al., pp. 339-370. New York: Kluwer Academic/Plenum 2002.
Recorded from the mid 16th century, the word is of unknown origin, perhaps from Low German; in the Middle Low German version of Reynard the Fox (1498), Moneke appears once as the name of the son of Martin the Ape.
as artful as a wagonload of monkeys extremely clever or mischievous.
monkey business mischievous or deceitful behaviour.
a monkey on one's back a burdensome problem.
Monkey Trial a trial of a teacher for teaching evolutionary theories, contrary to the laws of certain States of the US, specifically that of J. T. Scopes in Dayton, Tennessee (10–21 July, 1925), with William Jennings Bryan for the prosecution, and Clarence Darrow for the defence. Scopes was convicted, and fined $100 dollars.
three wise monkeys a conventional sculptured group of three monkeys; used allusively to refer to a person who chooses to ignore or keep silent about wrongdoing. One monkey is depicted with its paws over its mouth (taken as connoting ‘speak no evil’), one with its paws over its eyes (‘see no evil’), and one with its paws over its ears (‘hear no evil’).
See also cold enough to freeze the balls off a brass monkey, if you pay peanuts, you get monkeys.