Photographs by George F. Mobley (langur monkey), Michael Nichols (baboon baby), Tim Laman (squirrel monkey), Joel Sartore (vervet monkey), Tim Laman (pygmy marmoset), Michael Nichols (mandrill), Tim Laman (titi monkey), Robert Sisson (colobus monkey), and Jodi Cobb (macaque), all National Geographic

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    On December 14, 2000, Monkey Day was first celebrated by college students in Lansing, Michigan. Today, the day is a chance to celebrate simians of all shapes and sizes.
    Monkey Day does not just celebrate monkeys—it hopes to bring awareness to all primates. Primates include prosimians, monkeys, and apes. Prosimians are primates that usually have whiskers and extended snouts. Lemurs and bushbabies are prosimians. Monkeys are primates that usually have tails. Some of the world’s most familiar monkeys are baboons and capuchin monkeys. Apes are primates without tails, and with flexible shoulder joints that make it easy for them to swing from tree branches. (Monkeys have a smaller range of motion and usually run along on top of tree branches.) Gorillas, chimpanzees, and orangutans are all apes. 
    Many of the world’s primates are threatened by loss of habitat. Some of the most endangered species of primates are langurs, a type of monkey native to Southeast Asia. Langurs are losing their habitat to agriculture, logging, and housing.
  • Term Part of Speech Definition Encyclopedic Entry
    agriculture Noun

    the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching).

    Encyclopedic Entry: agriculture
    ape Noun

    large, intelligent primate with no tail.

    celebrate Verb

    to observe or mark an important event with public and private ceremonies or festivities.

    endangered species Noun

    organism threatened with extinction.

    Encyclopedic Entry: endangered species
    flexible Adjective

    able to bend easily.

    habitat Noun

    environment where an organism lives throughout the year or for shorter periods of time.

    Encyclopedic Entry: habitat
    humid Adjective

    air containing a large amount of water vapor.

    jungle Noun

    tropical ecosystem filled with trees and underbrush.

    logging Noun

    industry engaged in cutting down trees and moving the wood to sawmills.

    monkey Noun

    mammal considered to be highly intelligent, with four limbs and, usually, a tail.

    primate Noun

    type of mammal, including humans, apes, and monkeys.

    prosimian adjective, noun

    grouping of primates, including lemurs, lorises, and tarsiers.

    rainforest Noun

    area of tall, mostly evergreen trees and a high amount of rainfall.

    Encyclopedic Entry: Rainforest
    simian Noun

    ape or monkey.

    snout Noun

    protruding nose and jaw of an animal such as a pig.

    threaten Verb

    to scare or be a source of danger.