• A zoo is a place where animals live in captivity and are put on display for people to view. The word “zoo” is short for “zoological park.” Zoos contain wide varieties of animals that are native to all parts of the Earth.

    Though people have kept wild animals for thousands of years, those collections have not always resembled modern zoos. The first zoos were created as private collections by the wealthy to show their power. These private collections were called menageries.

    Wall carvings found in Egypt and Mesopotamia are evidence that rulers and aristocrats created menageries as early as 2500 BCE. They left records of expeditions to distant places to bring back exotic animals such as giraffes, elephants, bears, dolphins, and birds. There is evidence that ancient zoo owners hired animal handlers to make sure their animals thrived and reproduced.

    Zoos also existed in later civilizations, including China, Greece, and Rome. The Aztec emperor Montezuma II, in what is today Mexico, maintained one of the earliest animal collections in the Western Hemisphere. It was destroyed by Hernan Cortes during the Spanish conquest in 1520.

    Modern Zoos

    The model of the modern, public zoo became popular in 18th century, during the Age of Enlightenment. The Age of Enlightenment was a period in European history when science, reason, and logic were promoted as ideals of society and government. The scientific focus of the Age of Enlightenment extended to zoology.

    During this time, people started wanting to study animals for scientific reasons. Scientists wanted to research animal behavior and anatomy. To do this, scientists and zookeepers had to keep animals in places that were close to, or resembled, the animals’ natural habitats.

    The first modern zoo, built in 1793, opened in Paris, France. The menageries of French aristrocrats, including the king and queen, were taken by leaders of the French Revolution and relocated to the Ménagerie du Jardin des Plantes. The facility is still a busy and popular zoo in downtown Paris.

    Early zoos like the Menagerie du Jardin des Plantes were more like museums of living animals than natural habitats. Animals were kept in small display areas, with as many species as space would allow.

    Today, zoos are meant to entertain and educate the public but have a strong emphasis on scientific research and species conservation. There is a trend toward giving animals more space and recreating natural habitats. Zoos are usually regulated and inspected by the government.

    Types of Zoos

    Urban and Suburban Zoos
    Urban zoos, located in large cities, still resemble the smaller zoos that were popular 200 years ago. Often, these zoos sit in the middle of cities, making expansion difficult. There is little room for urban zoos to grow, and many of the zoo’s buildings are historic landmarks that cannot be destroyed or redesigned.

    In many urban zoos, animals are kept in relatively small enclosures. Some animal activists argue that keeping animals in urban settings is cruel because of cramped conditions, noise, and pollution.

    Urban zoos are common in Europe, while many zoos in the United States developed as sprawling parks in suburbs outside cities. These open-range zoos give animals more territory to roam and provide more natural habitats. This popular technique of building realistic habitats is called landscape immersion.

    The San Diego Zoo, in southern California, is the largest zoo in the United States. It is a suburban zoo that houses more than 4,000 animals (800 different species) in its 0.4 square kilometers (100 acres). Landscape immersion divides animals into their natural habitats, such as the tundra (with reindeer and polar bears) or bamboo forest (featuring pandas.) The San Diego Zoo also includes a wild animal park, which is even more expansive (almost 8 square kilometers or 2,000 acres.)

    Safari Parks
    Larger than urban and open-range zoos, safari parks are areas where tourists can drive their own cars to see non-native wildlife living in large, enclosed areas. These attractions allow the animals more space than the small enclosures of traditional zoos.

    Fuji Safari Park, in Susono, Japan, offers a traditional zoo as well as a drive-through safari park. Visitors can take their own cars or one of the park’s buses. Fuji Safari Park offers night tours, so visitors can see nocturnal animals, or animals that are active at night. At the park, visitors can also feed some animals, such as lions, from bus windows. Not all parks encourage or even allow visitors to feed animals.

    Safari parks, especially in Europe, are often part of larger theme parks or resorts. They include golf courses and fairground attractions, such as games and rides.

    Game Reserves
    Game reserves are large swaths of land whose ecosystems and native species are protected. The protections allow animals to live and reproduce at natural rates. Animals are allowed to roam free.

    In the 1800s, a trip to hunt “big game” (large animals such as elephants or lions) was called a safari. While some game reserves allow traditional hunting safaris today, others limit visitors to a “photo safari,” where visitors can shoot photographs, not animals.

    Animals in all game reserves are protected from illegal hunting, which is a threat to many endangered species. Legal hunts are regulated by the government. Hunters must purchase licenses and are strictly limited to the type and number of animals they can hunt. Poachers, or hunters without licenses, kill animals for valuable body parts. Elephants, for example, are killed by poachers for their ivory tusks.

    There are game reserves in Asia, the Americas, and Australia. However, most game reserves are in Africa. Millions of visitors flock to sites across Africa to see the same animals that captivated audiences thousands of years ago. The biggest attractions are Africa’s “Big Five” species—lions, leopards, rhinoceroses, elephants, and water buffalo. The Big Five are not Africa’s largest species (although the elephant is): They are the most difficult to find and, when legal, to hunt.

    Only recently has a single zoo, Gondwana Game Reserve in South Africa, offered all Big Five animals in one place. Gondwana sits on 10,000 hectares (24,710 acres) near the center of South Africa’s southern coast. Like many large game reserves, Gondwana has diverse ecosystems that occur naturally and has no need for landscape immersion. In Gondwana, grasslands coexist with shrubland called fynbos. Visitors to Gondwana, like many game reserves, can stay in hotels right in the park.

    Petting zoos
    Petting zoos feature domesticated animals that are gentle enough for children to pet and feed. Sheep, goats, donkeys, and rabbits are common petting zoo animals.

    These types of zoos are found at parks and inside of larger zoos. Sometimes mobile petting zoos travel with fairs or carnivals from city to city.


    Most zoos have specialized enclosures and habitats for specific animals. Zoos in cold climates, such as Novosibirsk, Russia, must recreate warm ecosystems for animals like lemurs. Lemurs are a type of primate native to the island of Madagascar, off Africa’s east coast. The summer temperatures of both Siberia and Madagascar are about the same—around 21 degrees Celsius (70 degrees Fahrenheit).

    However, Madagascar receives about 200 to 250 millimeters (8 to 10 inches) of rain each summer, making it a humid jungle environment. Novosibirsk gets just 60 to 65 millimeters (2 to 3 inches) of rain and snow. The difference in winter temperatures is even more drastic: Madagascar is about 15 degrees Celsius (59 degrees Fahrenheit). Lemurs’ fur can keep them warm at this temperature. Winter in Novosibirsk is -10 degrees Celsius (13 degrees Fahrenheit). The Novosibirsk Zoo has two species of lemur with a specialized heated enclosure with high humidity.

    Some zoos are dedicated entirely to certain species. Aquariums are types of zoos that exclusively house aquatic animals. The Sydney Aquarium in Australia has exhibits of all of Australia’s major water systems and is home to more than 650 native Australian species.

    Aviaries and bird parks are another type of specialized zoo. The Jurong Bird Park in Singapore has more than 8,000 birds of 600 species from around the world. Jurong has more than 1,000 flamingoes in an African wetlands exhibit that features a daily simulated thunderstorm.


    The World Association of Zoos and Aquariums, the international organization for zoos, is concerned with the health of animals in zoos. The focus of environmental efforts takes the form of research, captive breeding of rare animals, and conservation.

    Researchers at zoos can study animals up-close. They can observe behavior such as mating and nutrition choices. Biologists and veterinarians are also available to treat sick or injured animals.

    Captive breeding of endangered species makes zoos valuable places for animal survival. Animals such as the black soft-shelled turtle, native to India and Bangladesh, are extinct in the wild. But they survive in several zoos around the world, with their health looked after by biologists.

    The goal of many captive breeding programs at zoos is the re-introduction of animals into the wild. The California condor, a very large bird native to the west coast of the United States, has been re-introduced to its native habitat after breeding in zoos and wildlife parks. There are several breeding pairs of California condors in the wild today.

    Critics of captive breeding programs say that releasing a few animals into the wild does little to help the species population. Animals are extinct in the wild largely due to loss of habitat. The re-introduction of animals, especially large mammals that require vast territory for survival, does nothing to recover lost habitat. People continue to develop land for homes and businesses.

    Zoos often have conservation projects in the native habitats of the animals they keep in captivity. For instance, the World Association of Zoos and Aquariums established a partnership with people in rural Papua New Guinea to save tree kangaroos. These rare species are threatened by loss of habitat and the growing population of Papua New Guinea: Villagers hunt the tree kangaroo for meat. A zoo program introduced a rabbit-farming program to address the nutritional needs of the villagers. Zoos also set up conservation sites where the hunting of tree kangaroos was outlawed.

    While zoos have put more importance on conservation and humane animal treatment in recent decades, some critics say it is cruel to keep animals in captivity. Critics argue that living in captivity takes away wild animals’ natural behavior and instincts. Supporters of zoos say they play an important role in protecting endangered species.

    Modern Menageries
    People still enjoy collecting animals to display in their private homes. The American entertainer Michael Jackson, for instance, had a menagerie that included tigers, giraffes, parrots, and, of course, his pet chimpanzee, Bubbles.

    The Colombian drug lord Pablo Escobar kept an enormous private zoo that included elephants, buffalo, and camels. Some of Escobar's hippopotamuses, native to Africa, escaped into the Colombian jungle. After Escobar's death, the rest of the animals were sold or donated to zoos around the world.

    City of Brotherly Animals
    The first zoo in the United States opened in Philadelphia, Pennsylvania, in 1874. The Philadelphia Zoo remains one of the most important zoos and facilities for breeding rare and endangered animals.

    Many books of fiction, nonfiction, and historical fiction concern zoos.

    Life of Pi is a novel by Canadian author Yann Martel. The father of the main character, Pi, is a zookeeper at the Pondicherry Zoo in India. When traveling across the Pacific Ocean, from India to Toronto, Canada, the boat carrying Pi, his family, and all the animals of the zoo sinks. The only survivors, alone on a lifeboat in the middle of the ocean, are Pi and the zoo's Bengal tiger, whose name is Richard Parker.

    Faithful Elephants: A True Story of Animals, People, and War is a nonfiction book written by Yukio Tsuchiya and illustrated by Ted Levin. The book tells the story of three elephants of the Uneo Zoo in Tokyo, Japan, in the time leading up to World War II.

    Pride of Baghdad is a graphic novel written by Brian K. Vaughn and illustrated by Niko Henrichon. The factual story, of lions that escaped from the Baghdad Zoo as the war in Iraq began, is told from the lions' point of view.

  • Term Part of Speech Definition Encyclopedic Entry
    Age of Enlightenment Noun

    (1700s) period in European history where science and reason were promoted as ideals of good citizens and society.

    anatomy Noun

    structure of an organism.

    aquarium Noun

    a container or tank where aquatic plants and animals are kept, or an institution that keeps such containers.

    aquatic Adjective

    having to do with water.

    aviary Noun

    enclosed area where birds are kept.

    Aztec Noun

    people and culture native to Mexico and Central America.

    bamboo Noun

    type of huge, woody grass.

    behavior Noun

    anything an organism does involving action or response to stimulation.

    Big Five Noun

    most difficult animals in Africa to hunt on foot: lion, African elephant, cape buffalo, leopard, and black rhinoceros.

    big game Noun

    large wild animals.

    biologist Noun

    scientist who studies living organisms.

    breeding pair Noun

    animals who cooperate over a period of time to produce generations of offspring.

    California condor Noun

    largest land bird of North America, with a wingspan of 3 meters (9.5 feet).

    captivate Verb

    to hold the attention of.

    captive breeding Noun

    reproduction of rare species controlled by humans in a closed environment, such as a zoo.

    carnival Noun

    traveling show with games, performances, and food.

    civilization Noun

    complex way of life that developed as humans began to develop urban settlements.

    Encyclopedic Entry: civilization
    climate Noun

    all weather conditions for a given location over a period of time.

    Encyclopedic Entry: climate
    coast Noun

    edge of land along the sea or other large body of water.

    Encyclopedic Entry: coast
    conquest Noun


    conservation Noun

    management of a natural resource to prevent exploitation, destruction, or neglect.

    Encyclopedic Entry: conservation
    cramped Adjective

    crowded or having very little space.

    destroy Verb

    to ruin or make useless.

    domesticate Verb

    to tame or adapt for human use.

    drastic Adjective

    severe or extreme.

    ecosystem Noun

    community and interactions of living and nonliving things in an area.

    Encyclopedic Entry: ecosystem
    enclosure Noun

    area surrounded by a wall, fence, or other physical boundary.

    endangered species Noun

    organism threatened with extinction.

    Encyclopedic Entry: endangered species
    exhibit Noun

    display, often in a museum.

    exotic Adjective

    foreign or strange.

    expansion Noun

    process of enlarging.

    expedition Noun

    journey with a specific purpose, such as exploration.

    extend Verb

    to enlarge or continue.

    extinct Adjective

    no longer existing.

    extinct in the wild Noun

    highest level of conservation of a living species, when the only living members of that species are protected in captivity such as zoos or aquariums.

    forest Noun

    ecosystem filled with trees and underbrush.

    French Revolution Noun

    (1789-1799) period in France when the monarchy ended and the country was a republic.

    fur Noun

    thick hair covering the skin of an animal.

    fynbos Noun

    shrub vegetation region native to the southwest coast of South Africa.

    game reserve Noun

    area of land filled with wildlife and preserved for hunting or tourism.

    Gondwana Game Reserve Noun

    large zoological park in South Africa.

    government Noun

    system or order of a nation, state, or other political unit.

    grassland Noun

    ecosystem with large, flat areas of grasses.

    habitat Noun

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

    Encyclopedic Entry: habitat
    Hernan Cortes Noun

    (1485-1547) Spanish explorer and conqueror of what is now Mexico.

    humane Adjective

    kind or gentle.

    humid Adjective

    air containing a large amount of water vapor.

    hunt Verb

    to pursue and kill an animal, usually for food.

    illegal Adjective

    forbidden by law.

    instinct Noun

    natural motivation or behavior.

    international organization Noun

    unit made up of governments or groups in different countries, usually for a specific purpose.

    Encyclopedic Entry: international organization
    ivory Noun

    hard, white substance that forms the teeth or tusks of some animals.

    jungle Noun

    tropical ecosystem filled with trees and underbrush.

    landmark Noun

    a prominent feature that guides in navigation or marks a site.

    landscape immersion Noun

    process of building realistic habitats for animals in zoos.

    lemur Noun

    type of small mammal (primate).

    logic Noun

    system of scientific or researched reason.

    mammal Noun

    animal with hair that gives birth to live offspring. Female mammals produce milk to feed their offspring.

    mate Verb

    to reproduce or breed.

    menagerie Noun

    private collection of animals.

    Menagerie du Jardin des Plantes Noun

    zoo in Paris.

    Mesopotamia Noun

    ancient region between the Tigris and Euphrates Rivers, today lying mostly in Iraq.

    Montezuma II Noun

    (1470-1520) Aztec emperor.

    museum Noun

    space where valuable works of art, history, or science are kept for public view.

    native species Noun

    species that occur naturally in an area or habitat. Also called indigenous species.

    nocturnal Adjective

    active at night.

    nutrition Noun

    process by which living organisms obtain food or nutrients, and use it for growth.

    petting zoo Noun

    area where domestic animals are kept for visitors to pet and feed.

    poacher Noun

    person who hunts or fishes illegally.

    primate Noun

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

    promote Verb

    to encourage or help.

    public Adjective

    available to an entire community, not limited to paying members.

    rain Noun

    liquid precipitation.

    Encyclopedic Entry: rain
    reason Verb

    to form thoughts and make connections based on facts and logic.

    reproduce Verb

    to create offspring, by sexual or asexual means.

    research Noun

    scientific observations and investigation into a subject, usually following the scientific method: observation, hypothesis, prediction, experimentation, analysis, and conclusion.

    resemble Verb

    to look like.

    resort Noun

    facility or space people go to relax in a luxury setting.

    roam Verb

    to wander or travel over a wide area without a specific destination.

    rural Adjective

    having to do with country life, or areas with few residents.

    safari Noun

    trip to investigate, hunt, or photograph big game animals.

    safari park Noun

    zoo where visitors can drive through open spaces filled with wild animals.

    San Diego Zoo Noun

    large zoological park in San Diego, California.

    science Noun

    knowledge focused on facts based on observation, identification, description, investigation, and explanation.

    shrub Noun

    type of plant, smaller than a tree but having woody branches.

    Siberia Noun

    region of land stretching across Russia from the Ural Mountains to the Pacific Ocean.

    simulate Verb

    to create an image, representation, or model of something.

    society Noun

    large community, linked through similarities or relationships.

    specialize Verb

    to study, work, or take an interest in one area of a larger field of ideas.

    specific Adjective

    exact or precise.

    sprawling Adjective

    spread out.

    suburb Noun

    geographic area, mostly residential, just outside the borders of an urban area.

    swath Noun

    path or line of material.

    temperature Noun

    degree of hotness or coldness measured by a thermometer with a numerical scale.

    Encyclopedic Entry: temperature
    theme park Noun

    amusement park where all attractions focus on one or more specific ideas, or themes.

    thrive Verb

    to develop and be successful.

    thunderstorm Noun

    cloud that produces thunder and lightning, often accompanied by heavy rains.

    tourist Noun

    person who travels for pleasure.

    tree kangaroo Noun

    type of mammal (marsupial).

    tundra Noun

    cold, treeless region in Arctic and Antarctic climates.

    urban Adjective

    having to do with city life.

    vast Adjective

    huge and spread out.

    veterinarian Noun

    person who studies the health of animals.

    wealthy Adjective

    very rich.

    Western Hemisphere Noun

    area of the Earth west of the prime meridian and east of the International Date Line.

    wetland Noun

    area of land covered by shallow water or saturated by water.

    Encyclopedic Entry: wetland
    wildlife Noun

    organisms living in a natural environment.

    World Association of Zoos and Aquariums Noun

    international organization for zoological parks.

    zoo Noun

    place where animals are kept for exhibition.

    Encyclopedic Entry: zoo
    zoological Adjective

    having to do with animals.

    zoology Noun

    the study of animals.