Zoo

Article Outline

Introduction; Zoo Operation; Importance of Zoos; History of Zoos; Contemporary Zoo Issues

Introduction

Zoo, also known as zoological garden or zoological park, institution devoted to the exhibition, preservation, and study of animals. Although most people visit zoos for entertainment, zoos also educate the public about animal behavior, natural habitats, and the plight of animals in danger of extinction. Zoos play a role in the conservation of threatened or endangered animals by developing innovative breeding programs to maintain populations of species that are in decline. Zoos also conduct scientific research on animal diseases, nutrition, reproduction, and behavior.

At the beginning of the 20th century most zoos captured animal specimens in the wild and displayed these animals like museum exhibits, enclosing them in small cages that gave the animals few opportunities to behave in a natural way. Today most zoos make animal welfare their highest priority. Whenever possible, animals are housed in specially designed enclosures that mimic their natural habitats. Zoo officials also use care when building up their animal collections. To avoid decimating animal populations in the wild, zoos no longer rely on newly captured specimens to stock their collections. Instead they now try to breed a significant proportion of their animals using captive animals.

Zoos employ several kinds of workers to care for animals. Zoologists (scientists who study animals) arrange captive breeding programs and make decisions about the types of species put on public display and the housing conditions they need, while veterinarians are concerned with animal health (see Veterinary Medicine). Zookeepers tend to the day-to-day welfare of the animals in their charge, including feeding and grooming animals and maintaining enclosures. They often deal with questions from visitors. All of these positions require at least a bachelor’s degree in biology, zoology, or another animal-related field, as well as firsthand experience with animals.

Most large zoos house a wide variety of species to attract visitors, but some also focus on species that are in special need of protection. In the United States, the Cincinnati Zoo in Ohio has been particularly successful in breeding lowland gorillas, whose populations in their natural habitat of Africa have declined due to poaching and human encroachment. Both the Los Angeles Zoo and the San Diego Zoo in California have used novel captive-breeding techniques to prevent the extinction of the California condor. In 1987 fewer than two dozen of these condors remained in the wild, but zoo-based breeding has since increased the total population.

Zoo Operation

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Zoos require specialized buildings and skilled staff, and as a result zoos are expensive to run and to maintain. Obtaining sufficient funds is essential for a zoo’s survival. In the United States and in most other developed countries, zoos are usually financed by funds from cities or states, and by entry fees paid by the visiting public. Zoos also encourage supporters to help finance their research programs.

A number of national and international organizations help zoos coordinate their work. The World Association of Zoos and Aquariums (WAZA) headquartered in Switzerland is the umbrella organization for zoos and aquariums worldwide. In the United States, the American Zoo and Aquarium Association (AZA), headquartered in Maryland, coordinates the work of zoos and requires that its members maintain the highest levels of animal care. The AZA also manages the Species Survival Plan (SSP), which currently protects more than 120 animal species that are endangered or threatened in the wild. The SSP organizes captive breeding among genetically diverse animals from different zoos around North America as an insurance policy against extinction. They also arrange the release of captive-bred animals back into the wild.

Zoo Exhibits

In the early 20th century, zoos kept large animals in cages with steel bars. These sterile environments, coupled with ever-present gawking visitors, prevented animals from performing natural acts such as mating and hunting for food. By the second half of the 20th century zoos had begun to create exhibits designed more for the benefit of the animals. Zoos constructed large enclosures in which landscaping and terrain simulated the natural environments of the African savanna, North American prairie, or Amazon rain forests. Large mammals, such as elephants, rhinoceroses, and bears, are now often kept in these open-air enclosures ringed by deep ditches.

Many of the world’s leading zoos now have giant aviaries—large enclosures that visitors can walk through to watch birds nesting and flying overhead. At the San Diego Zoo, for example, the Scripps Aviary contains more than 200 species of birds from the African tropics. The birds are housed in a huge enclosure complete with rain forest plants.

On a smaller scale, some zoos have created climate-controlled butterfly houses where visitors can view tropical species. At the Perth Zoo in Australia, visitors step into an 800 sq m (1,000 sq yd) enclosure to view hundreds of butterflies from more than 28 species feeding on nectar from flowers or on sugary juices from fruit. Often these insects become so accustomed to people that they will even settle on clothing, something that rarely happens in the wild.

Many animals, including over two-thirds of the world’s mammal species, are nocturnal, sleeping by day and becoming active at night. Watching these animals under normal daytime conditions can be a disappointing experience. To solve this problem, many zoos now have nocturnal houses, in which special lighting is used to reverse night and day. During the night, the interior of the house is brightly lit, while during the day, a dim light mimics the nighttime but still enables daytime visitors to see the animals without disrupting their nocturnal activity. This day-for-night swap gives visitors a chance to watch nocturnal hunters, such as members of the cat family and civets, as well as fruit-eating bats.

Animal Parks

Most zoos were founded in cities where they were easily accessible to visitors. These city-center sites proved to have drawbacks, however. Many large animals—particularly herding species—need space in order to breed, and in cities that space can be hard to find. Several leading zoos solved this problem either by moving or by obtaining open land where animals could be given the room they need. In 1931 the London Zoo pioneered this approach when it acquired nearly 200 hectares (500 acres) at Whipsnade Park, an outdoor reserve that has since become one of the world’s prime breeding centers for rare crocodiles, black rhinoceroses, and Przewalski’s horses. The San Diego Zoo, which opened on a 40-hectare (100-acre) site in 1916, followed the strategy on an even bigger scale when it created the 730-hectare (1,800-acre) San Diego Wild Animal Park, located in Escondido, California. The park allows visitors to see animals roaming free in a variety of landscapes that look uncannily like their natural habitats. Parks like these have become immensely popular attractions, and the income they generate helps zoos meet the expense involved in raising endangered animals.

In constructing animal parks, zoo architects create a large protected area that appears limitless but in fact has carefully concealed fences and boundaries to protect animals. A variety of methods are used in an animal park to mimic the terrain of a far-off habitat. For instance, the San Diego Wild Animal Park is nestled in the San Pasqual Valley, an area in California that is similar to the African savanna. Zoo architects further enhance the feeling of an African plain by using extensive landscaping and hidden irrigation systems.

Zoo architects consider the needs of animals in the wild before making any environmental enhancements to the animal park. Tall trees are provided to accommodate the browsing needs of the tall-necked giraffes. Tree stumps are left in the ground for rhinoceroses to use as rubbing posts. Foliage in some areas provides shelter or privacy for animals, while other areas are left barren of grass or other plants to enable animals such as zebras to roll in the dirt to repel insects.

When animals feel comfortable in their habitat, they are able to perform natural courtship, mating, and nurturing. As a result, in many cases animal parks maintain the best success rate for captive breeding and newborn survival. Often animals that have been raised in a traditional zoo are released into an animal park as a test to determine whether they will be successful candidates for reintroduction into the wild.

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Introduction

Zoo Operation

Zoo Exhibits

Animal Parks