Yahoo Web Search

Search results

  1. People also ask

  2. Almost all monkeys have tails; apes do not. Their bodies are different in other ways too: monkeys are generally smaller and narrow-chested, while apes are larger and have broad chests and shoulder joints that allow them to swing through trees (while some monkeys also have this ability, most of them are built for running across branches rather ...

    • Alison Eldridge
  3. Mar 6, 2024 · A study suggests a single mutation in a gene called TBXT caused the ancestors of humans and apes to lose their tails around 25 million years ago. The mutation might have been beneficial for upright posture and bipedal movement, but also led to spina bifida defects in some cases.

    • Overview
    • Old World monkeys versus New World monkeys
    • Classification

    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 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 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 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 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 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 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 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 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.

    Are you a student? Get Britannica Premium for only 24.95 - a 67% discount!

    Learn More

    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.

    •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.

  4. Feb 29, 2024 · They found an insertion of DNA that is shared by apes and humans, but is not present in monkeys. It is located on a gene called TBXT, which is known to affect animal tail length. Once they...

  5. Monkey tails, also known as caudal appendages, come in a wide array of shapes and sizes. From the slender, prehensile tails of spider monkeys to the short, non-prehensile tails of macaques, each species has evolved a tail that suits its specific needs.

  6. Feb 28, 2024 · A study suggests that a single insertion of an Alu element into a gene called Tbxt around 25 million years ago caused tail loss in apes. The gene is involved in vertebrate tail development and mice with apelike versions of the gene have shorter or no tails.

  7. Sep 24, 2021 · A genetic mutation in a tail gene called TBXT caused apes to lose their tails suddenly, according to a study. The mutation involves an Alu element that glues some of the protein instructions together, resulting in incomplete TBXT protein.

  1. People also search for