Search Britannica... Browse Dictionary Quizzes Home Science Mammals Primates monkey primate Print Cite Share Feedback Written by Colin Peter Groves Fact-checked by The Editors of Encyclopaedia Britannica Last Updated: Jan 4, 2023 • Article History Table of Contents Summary Read a brief summary of this topic monkey, in general, any of nearly 200 species of tailed primate, with the exception of lemurs, tarsiers, and lorises. The presence of a tail (even if only a tiny nub), along with their narrow-chested bodies and other features of the skeleton, distinguishes monkeys from apes. Most monkeys have a short, relatively flat face without great prominence of the muzzle, although baboons and mandrills are notable exceptions. The vast majority of species live in tropical forests, where Old World and New World monkeys See all media Related Topics: cuscus • Old World monkey • New World monkey • anthropoid they move on all four limbs. All but the durukuli of tropical Central and South America are active during the day moving frequently in bands as See all related content → Money Video Subscribe Login during the day, moving frequently in bands as they search for vegetation, birds’ eggs, smaller animals, and insects to eat. Monkeys are capable of sitting upright, and, consequently, their hands are freed for many manipulative tasks. Except for a few Old World forms, monkeys are predominantly arboreal, leaping from limb to limb in their travels among the trees. Their hands and feet are both used for grasping and typically have five digits, the thumb and big toe being divergent from the others. Commonly, the digits have flattened nails, but the marmosets have claws on all digits except the big toe, which bears a nail. On the ground, monkeys walk with the entire sole of the foot touching the ground but with the palm of the hand raised. They almost never walk on two legs (bipedally) and can stand erect for only short periods, if at all. Monkeys have large brains and are known for their inquisitiveness and intelligence. Brain development, combined with the freeing of the hands and well-developed vision, allows them a great latitude of activity. Most are good at solving complex problems and learning from experience, but they do not quite reach the cognitive levels of great apes. Some, especially the capuchins (genus Cebus), spontaneously use common squirrel monkey objects as tools (e.g., stones to crack nuts). Others, such as baboons, readily learn to use sticks to obtain food. However, in strong contrast to the great apes (gorillas, chimpanzees, and orangutans), most monkeys do not appear to be very good at learning from each others’ experience—individuals more or less have to learn new behaviours for themselves. A significant exception is the Japanese macaque (Macaca fuscata). In field experiments, these monkeys were introduced to new foods such as sweet potatoes and candies wrapped in paper. Once a few individuals had solved the problems of getting at the new foods, their innovations gradually spread throughout entire troops. These experiments have had implications in redefining cultural behaviour. Britannica Quiz A Is for Animal Quiz Monkeys are highly social animals, and almost all live in troops consisting of several females with young and either a single male (as in hamadryas baboons, mandrills, most guenons, and most langurs) or several males (as in savannah baboons and macaques). Usually, but not universally, the females stay in the troop in which they were born and are thus closely related to each other. Males join new troops on maturity, and so they are unrelated to each other and somewhat antagonistic. Like humans and apes, female monkeys nurse their young and have a menstrual cycle, albeit less copious. In some species, sexual activity is strictly confined to the period around ovulation (estrus); in others, there appears to be little or mandrill no restriction. Some species breed all year round; others have a period several months long during which they experience no sexual cycles (anestrus). Old World monkeys versus New World monkeys Monkeys are arranged into two main groups: Old World and New World. Old World monkeys all belong to one family, Cercopithecidae, which is related to apes and humans, and together they are classified as catarrhines (meaning “downward-nosed” in Latin). The New World monkeys are the platyrrhines (“flat-nosed”), a group comprising five families. As their saki; macaque g oup co p s g ve a es. s t e taxonomic names suggest, New World (platyrrhine) and Old World (catarrhine) monkeys are distinguished by the form of the nose. New World monkeys have broad noses with a wide septum separating outwardly directed nostrils, whereas Old World monkeys have narrow noses with a thin septum and downward-facing nostrils, as do apes and humans. Old World monkeys have hard, bare “sitting pads” (ischial callosities) on the buttocks; New World monkeys lack these. Many Old World monkeys have thumbs that can be opposed to the other fingers and so can handle small objects precisely. None of the New World monkeys has such manual dexterity. Indeed, in the hands of many species, the main divergence is between the index and middle fingers; in a few species, the thumb is reduced or even absent. Some New World monkey species have prehensile tails capable of supporting the entire body weight or of grasping, for example, a proffered peanut. No Old World monkeys have this ability, and macaques are nearly tailless. New World monkeys live primarily in tropical South America, especially the Amazon rainforests; the range of a few species extends northward as far as southern Mexico or southward into northern Argentina. Among the smaller New World forms that have endeared themselves to humans with their antics and their tamability are the alert marmosets, often tufted and colourfully arrayed, and the inquisitive squirrel, woolly, and capuchin monkeys—all of which exhibit in marked degree the curiosity and cleverness ascribed to cotton-top tamarin monkeys generally. Larger New World species include the acrobatic spider monkeys and the noisy howlers. Other New World monkeys include uakaris, sakis, and titis. Old World monkeys live throughout Africa, on the Red Sea coast of Arabia, and in Asia from Afghanistan to Japan and southeast to the islands of the Philippines, Celebes, Bacan, and Timor. Some Old World monkeys have been successfully naturalized in Gibraltar, France, Mauritius, Belau, and a few islands of the West Indies. Old World monkeys include many that are often seen in zoos, especially the beautifully coloured African guenons (e.g., mona, diana, white-nosed, green, vervet, and grivet monkeys), colobus, mangabeys, and the chiefly Asiatic macaques. The macaques include the moustached monkey (Cercopithecus cephus) Barbary “ape” of North Africa and the Rock of Gibraltar—the only macaque outside Asia and the only wild monkey inhabiting any part of Europe today—and the rhesus monkey of the Indian subcontinent, which has been used considerably in medical research. The graceful langurs include the hanuman, or sacred monkey, also of southern Asia. Among the more unusual monkeys are the large and strikingly coloured African drills and mandrills, the proboscis monkey of Borneo, and the rare and bizarre snub-nosed k f Chi d Vi Th Old W ld k di id d i monkeys of China and Vietnam. The Old World monkeys are divided into two subfamilies: Cercopithecinae and Colobinae. The cercopithecines have cheek pouches, in which they store food; these include baboons, macaques, guenons, and their relatives. The colobines lack cheek pouches but have complicated three- or four-chambered stomachs, where bacterial fermentation of cellulose and hemicellulose occurs and thereby enriches the nutrient content of their diet, which consists partially of leaves and seeds. Colobines include colobus monkeys, langurs, and their relatives. Get a Britannica Premium subscription and gain access to exclusive content. Subscribe Now Because the ecological niches that they occupy are similar, there are many parallels between Old and New World monkeys. In particular, the squirrel monkeys (genus Saimiri) of the New World and the talapoin (genus Miopithecus) of West-Central Africa are remarkably convergent; both are small (about 1 kg [2.2 pounds]) and greenish, live in large troops along rivers, and breed seasonally. Other aspects of each group’s evolution, however, are unique. No New World monkey lives on the savanna or has a multichambered cellulose-fermenting stomach, and no Old World monkey is nocturnal like the durukuli. The closest analogue to the complex society of the spider monkey is found not in an Old World monkey but in the chimpanzee. Classification FAMILY CERCOPITHECIDAE (Old World monkeys) 103 or more species in 21 genera from Africa and Asia. The number of species stated within a given genus may vary, depending on the taxonomic criteria used. Subfamily Cercopithecinae 63 or more species in 11 genera. Cercopithecus (guenons) 20 or more African species. Macaca (macaques) 20 or so Asian and African species. Cercocebus (mangabeys) 7 African species. Papio (baboons) 5 African and Arabian species. Lophocebus (mangabeys) 3 African species. Mandrillus (drills and mandrills) 2 African species. Miopithecus (talapoins) 2 African species. Allenopithecus (Allen’s swamp monkey) 1 African species. Chlorocebus (vervet, or green monkey) 1 to 6 African species. Erythrocebus (patas monkey) 1 African species. Theropithecus (gelada) 1 African species. Subfamily Colobinae 40 or more species in 10 genera. Trachypithecus (brow-ridged langurs) 10 or more Southeast Asian species. Presbytis (leaf monkeys) 8 Southeast Asian species. Colobus (black-and-white colobus monkeys) 5 African species. Procolobus (olive colobus monkeys) 5 to 10 African species. Rhinopithecus (snub-nosed monkeys) 4 Asian species. Pygathrix (doucs) 3 continental Southeast Asian species. Semnopithecus 2 to 8 South Asian species, including the Hanuman langur. Nasalis (proboscis monkey) 1 Indonesian species. Procolobus (red colobus monkey) 1 African species. Simias (simakobu, or pig-tailed langur) 1 Indonesian species. PLATYRRHINII (New World monkeys) 94 or more species in 5 families from tropical Central and South America. The number of species stated within a given genus may vary, depending on the taxonomic criteria used. Formerly, only two families were recognized within the group: Callitrichidae (marmosets and tamarins) and Cebidae (all others, including capuchins, titis, squirrel monkeys, and howler monkeys). Molecular evidence, together with reassessments of morphological evidence, now indicates that marmosets are more related to the capuchins, with spider monkeys and their relatives being more divergent. Recent classifications, therefore, tend to recognize additional families: Atelidae (spider monkeys and their relatives), Pitheciidae (sakis and uakaris), and Aotidae (durukulis); Callitrichidae and Aotidae are sometimes lumped into the Cebidae. Family Callitrichidae (marmosets and tamarins) 27 or more species in 4 genera. Sometimes included in the family Cebidae as a subfamily. Saguinus (tamarins) 12 or more species. Callithrix (“true” marmosets) 10 to 20 species. 0 to 0 spec es. Leontopithecus (lion tamarins) 4 species. Callimico (Goeldi’s monkey) 1 species. Family Pitheciidae 29 or so species in 4 genera. Subfamily Callicebinae Callicebus (titis) 20 or so species. Subfamily Pitheciinae (sakis and uakaris) Pithecia (sakis) 5 species. Chiropotes (bearded sakis) 2 species. Cacajao (uakaris) 2 species. Family Atelidae 19 or more species in 5 genera. Subfamily Atelinae ( spider and woolly monkeys) Ateles (spider monkeys) 4 to 8 species. Lagothrix (woolly monkeys) 4 species. Brachyteles (muriquis, or woolly spider monkeys) 2 species. Oreonax (yellow-tailed, or Hendee’s, woolly monkey) 1 species. Family Cebidae (capuchin and squirrel monkeys) 10 or more species in 2 genera. Cebus (capuchin monkeys) 5 to 8 species. Saimiri (squirrel monkeys) 5 to 8 species. Family Aotidae Aotus (durukulis, or night monkeys) 9 species. Colin Peter Groves Table of Contents Sivapithecus Home Science Earth Science, Geologic Time & Fossils Fossils & Geologic Time Sivapithecus fossil primate genus Print Cite Share Feedback Written and fact-checked by The Editors of Encyclopaedia Britannica Last Updated: Article History Table of Contents Sivapithecus, fossil primate genus dating from the Miocene Epoch (23.7 to 5.3 million years ago) Related Topics: orangutan • fossil • Miocene Epoch • anthropoid and thought to be the direct ancestor of the orangutan. Sivapithecus is closely related to Ramapithecus, and fossils of the two primates See all related content → have often been recovered from the same deposits in the Siwālik Hills of northern Pakistan. Other Sivapithecus remains have been found at sites in Turkey, Pakistan, China, Greece, and Kenya. Some authorities maintain that Sivapithecus and Ramapithecus are in fact the same species. Though Sivapithecus was slightly larger than Ramapithecus, it was only a small-to-medium-sized ape about the size of a modern chimpanzee. The fossil remains of Sivapithecus reveal that it shared many of the same specialized facial features of the orangutan—i.e., eyes set narrowly apart, a concave face, a smooth nasal floor, large zygomatic bones, and enlarged central incisors. Sivapithecus’ place in primate evolution was poorly understood until the 1980s. Prior to this, the genus, along with Ramapithecus, was interpreted as having both apelike and humanlike features and thus was presumed to be a possible first step in the evolutionary divergence of humans from the common hominoid stock of the apes. But new Sivapithecus finds and the reinterpretation of existing remains convinced most authorities in the 1980s that Sivapithecus was the ancestor of the modern orangutan and diverged from the common lineage of the African apes (i.e., chimpanzees and gorillas) and humans more than 13 million years ago. The earliest Sivapithecus remains found so far are about 17 million years old, and the most recent are about 8 million years old. Load Next Page Information from your device can be used to personalize your ad experience. Do not sell or share my personal information. PDFmyURL.com - convert URLs, web pages or even full websites to PDF online. Easy API for developers!
