A zoo (short for zoological garden; also called an animal park or menagerie) is a facility in which animals are kept within enclosures for public exhibition and often bred for conservation purposes.
The term zoological garden refers to
The London Zoo, which was opened in 1828, was initially known as the "Gardens and Menagerie of the Zoological Society of London", and it described itself as a menagerie or "zoological forest". The abbreviation "zoo" first appeared in print in the United Kingdom around 1847, when it was used for the Clifton Zoo, but it was not until some 20 years later that the shortened form became popular in the rhyming song "Walking in the Zoo" by music-hall artist Alfred Vance. The term "zoological park" was used for more expansive facilities in Halifax, Nova Scotia, Washington, D.C., and the Bronx in New York, which opened in 1847, 1891 and 1899 respectively.
Relatively new terms for zoos in the late 20th century are "
The predecessor of the zoological garden is the
At one time, bear and a bull, chained together, rolled in fierce combat across the sand ... Four hundred bears were killed in a single day under Caligula ... Under Nero, four hundred tigers fought with bulls and elephants. In a single day, at the dedication of the Colosseum by Titus, five thousand animals perished. Under Trajan ... lions, tigers, elephants, rhinoceroses, hippopotami, giraffes, bulls, stags, even crocodiles and serpents were employed to give novelty to the spectacle.
The oldest zoo in the world still in existence is the
The modern zoo
Until the early 19th century, the function of the zoo was often to symbolize royal power, like King Louis XIV's menagerie at Versailles. Major cities in Europe set up zoos in the 19th century, usually using London and Paris as models. The transition was made from princely menageries designed to entertain high society with strange novelties into public zoological gardens. The new goal was to educate the entire population with information along modern scientific lines. Zoos were supported by local commercial or scientific societies.
The modern zoo that emerged in the 19th century in the United Kingdom, was focused on providing scientific study and later educational exhibits to the public for entertainment and inspiration.
A growing fascination for
The Zoological Society of London was founded in 1826 by Stamford Raffles and established the London Zoo in Regent's Park two years later in 1828. At its founding, it was the world's first scientific zoo. Originally intended to be used as a collection for scientific study, it was opened to the public in 1847. The Zoo was located in Regent's Park - then undergoing development at the hands of the architect John Nash. What set the London zoo apart from its predecessors was its focus on society at large. The zoo was established in the middle of a city for the public, and its layout was designed to cater for the large London population. The London zoo was widely copied as the archetype of the public city zoo. In 1853, the Zoo opened the world's first public aquarium.
Downs' Zoological Gardens created by Andrew Downs and opened to the Nova Scotia public in 1847. It was originally intended to be used as a collection for scientific study. By the early 1860s, the zoo grounds covered 40 hectares with many fine flowers and ornamental trees, picnic areas, statues, walking paths, The Glass House (which contained a greenhouse with an aviary, aquarium, and museum of stuffed animals and birds), a pond, a bridge over a waterfall, an artificial lake with a fountain, a wood-ornamented greenhouse, a forest area, and enclosures and buildings.
The first zoological garden in Australia was Melbourne Zoo in 1860.
In German states leading roles came Berlin (1841), Frankfurt (1856), and Hamburg (1863). In 1907, the entrepreneur Carl Hagenbeck founded the Tierpark Hagenbeck in Stellingen, now a quarter of Hamburg. His zoo was a radical departure from the layout of the zoo that had been established in 1828. It was the first zoo to use open enclosures surrounded by moats, rather than barred cages, to better approximate animals' natural environments. He also set up mixed-species exhibits and based the layout on the different organizing principle of geography, as opposed to taxonomy.
The Wrocław Zoo (Polish: Ogród Zoologiczny we Wrocławiu) is the oldest zoo in Poland, opened in 1865 when the city was part of Prussia, and was home to about 10,500 animals representing about 1,132 species (in terms of the number of animal species, it is the third largest in the world). In 2014 the Wrocław Zoo opened the Africarium, the only themed oceanarium devoted solely to exhibiting the fauna of Africa, comprehensively presenting selected ecosystems from the continent of Africa. Housing over 10 thousand animals, the facility's breadth extends from housing insects such cockroaches to large mammals like elephants on an area of over 33 hectares.
In the United States, the Philadelphia Zoo, opened July 1, 1874, earning its motto "America's First Zoo." The Lincoln Park Zoological Gardens in Chicago and the Cincinnati Zoo opened in 1875. In the 1930s, federal relief programs provided financial aid to most local zoos. The Works Progress Administration and similar New Deal government agencies helped greatly in the construction, renovation, and expansion of zoos when the Great Depression severely reduced local budgets. It was "a new deal for animals."
By 2020, the United States featured 230 accredited zoos and aquariums across 45 states, accommodating 800,000 animals, and 6,000 species out of which about 1,000 are endangered. The zoos provide 208,000 jobs, and with an annual budget of $230 million for wildlife conservation. They attract over 200 million visits a year and have special programs for schools. They are organized by the Association of Zoos and Aquariums.
Japan's first modern zoo, Tokyo's Ueno Imperial Zoological Gardens, opened in 1882 based on European models. In World War II it was used to teach the Japanese people about the lands recently conquered by the Army. In 1943, fearing American bombing attacks, the government ordered the zoo to destroy dangerous animals that might escape.
Human beings were occasionally displayed in cages at zoos along with non-human animals, to illustrate the differences between people of
Human beings were also displayed at various events, especially colonial expositions such as the 1931
Zoo animals live in enclosures that often attempt to replicate their natural
Some zoos keep animals in larger, outdoor enclosures, confining them with
Roadside zoos are found throughout North America, particularly in remote locations. They are often small, for-profit zoos, often intended to attract visitors to some other facility, such as a gas station. The animals may be trained to perform tricks, and visitors are able to get closer to them than in larger zoos. Since they are sometimes less regulated, roadside zoos are often subject to accusations of neglect and cruelty.
In June 2014 the Animal Legal Defense Fund filed a lawsuit against the Iowa-based roadside Cricket Hollow Zoo for violating the Endangered Species Act by failing to provide proper care for its animals. Since filing the lawsuit, ALDF has obtained records from investigations conducted by the USDA's Animal and Plant Health Inspection Services; these records show that the zoo is also violating the Animal Welfare Act.
A petting zoo, also called petting farms or children's zoos, features a combination of
Animal theme parks
An animal theme park is a combination of an
Zoo population management
Sources of animals
By 2000 most animals being displayed in zoos were the offspring of other zoo animals.[
Dealing with space constraints and surplus animals
Especially in large animals, a limited number of spaces are available in zoos. As a consequence, various management tools are used to preserve the space for the genetically most important individuals and to reduce the risk of
Contraception can be an effective way to limit a population's breeding. However it may also have health repercussions and can be difficult or even impossible to reverse in some animals. Additionally, some species may lose their reproductive capability entirely if prevented from breeding for a period (whether through contraceptives or isolation), but further study is needed on the subject. Sale of surplus animals from zoos was once common and in some cases animals have ended up in substandard facilities. In recent decades the practice of selling animals from certified zoos has declined. A large number of animals are culled each year in zoos, but this is controversial. A highly publicized culling as part of population management was that of a healthy giraffe at Copenhagen Zoo in 2014. The zoo argued that its genes already were well-represented in captivity, making the giraffe unsuitable for future breeding. There were offers to adopt it and an online petition to save it had many thousand signatories, but the culling proceeded. Although zoos in some countries have been open about culling, the controversy of the subject and pressure from the public has resulted in others being closed. This stands in contrast to most zoos publicly announcing animal births. Furthermore, while many zoos are willing to cull smaller and/or low-profile animals, fewer are willing to do it with larger high-profile species.
Many animals breed readily in captivity. Zoos frequently are forced to intentionally limit captive breeding because of a lack of natural wild habitat in which to reintroduce animals. This highlights the importance of in situ conservation, or preservation of natural spaces, in addition to the utility of zoo captive breeding and reintroduction programs. In situ conservation and reintroduction programs are key elements to obtaining certification by reputable organisations such as the AZA.
Conservation and research
The position of most modern zoos in Australasia, Asia, Europe, and North America, particularly those with scientific societies, is that they display wild animals primarily for the conservation of endangered species, as well as for research purposes and education, and secondarily for the entertainment of visitors. The Zoological Society of London states in its charter that its aim is "the advancement of Zoology and Animal Physiology and the introduction of new and curious subjects of the Animal Kingdom." It maintains two research institutes, the Nuffield Institute of Comparative Medicine and the Wellcome Institute of Comparative Physiology. In the United States, the Penrose Research Laboratory of the Philadelphia Zoo focuses on the study of comparative pathology. The World Association of Zoos and Aquariums produced its first conservation strategy in 1993, and in November 2004, it adopted a new strategy that sets out the aims and mission of zoological gardens of the 21st century. When studying behaviour of captive animals, several things should however be taken into account before drawing conclusions about wild populations. Including that captive populations are often smaller than wild ones and that the space available to each animal is often less than in the wild.
Conservation programs all over the world fight to protect species from going extinct, but many conservation programs are underfunded and under-represented. Conservation programs can struggle to fight bigger issues like habitat loss and illness. It often takes a lot of funding and long time periods to rebuild degraded habitats, both of which are scarce in conservation efforts. The current state of conservation programs cannot rely solely on situ (on-site conservation) plans alone, ex situ (off-site conservation) may therefore provide a suitable alternative. Off-site conservation relies on zoos, national parks, or other care facilities to support the rehabilitation of the animals and their populations. Zoos benefit conservation by providing suitable habitats and care to endangered animals. When properly regulated, they present a safe, clean environment for the animals to increase populations sizes. A study on amphibian conservation and zoos addressed these problems by writing,
Whilst addressing in situ threats, particularly habitat loss, degradation and fragmentation, is of primary importance; for many amphibian species in situ conservation alone will not be enough, especially in light of current un-mitigatable threats that can impact populations very rapidly such as chytridiomycosis [an infectious fungal disease]. Ex situ programmes can complement in situ activities in a number of ways including maintaining genetically and demographically viable populations while threats are either better understood or mitigated in the wild 
The breeding of endangered species is coordinated by cooperative breeding programmes containing international studbooks and coordinators, who evaluate the roles of individual animals and institutions from a global or regional perspective, and there are regional programmes all over the world for the conservation of endangered species. In Africa, conservation is handled by the African Preservation Program (APP); in the U.S. and Canada by Species Survival Plans; in Australasia, by the Australasian Species Management Program; in Europe, by the European Endangered Species Program; and in Japan, South Asia, and South East Asia, by the Japanese Association of Zoos and Aquariums, the South Asian Zoo Association for Regional Cooperation, and the South East Asian Zoo Association.
Positive impacts on local wildlife
Besides conservation of captive species, large zoos may form a suitable environment for wild native animals such as herons to live in or visit. A colony of black-crowned night herons has regularly summered at the National Zoo in Washington, D.C. for more than a century. Some zoos may provide information to visitors on wild animals visiting or living in the zoo, or encourage them by directing them to specific feeding or breeding platforms.
In modern, well-regulated zoos, breeding is controlled to maintain a self-sustaining, global captive population. This is not the case in some less well-regulated zoos, often based in poorer regions. Overall "stock turnover" of animals during a year in a select group of poor zoos was reported as 20%-25% with 75% of wild caught apes dying in captivity within the first 20 months. The authors of the report stated that before successful breeding programs, the high mortality rate was the reason for the "massive scale of importations."
One 2-year study indicated that of 19,361 mammals that left accredited zoos in the U.S. between 1992 and 1998, 7,420 (38%) went to dealers, auctions, hunting ranches, unaccredited zoos and individuals, and game farms.
Animal welfare in zoos
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The welfare of zoo animals varies widely. Many zoos work to improve their animal enclosures and make it fit the animals' needs, but constraints such as size and expense can complicate this. The type of enclosure and the husbandry are of great importance in determining the welfare of animals. Substandard enclosures can lead to decreased lifespans, caused by factors as human diseases, unsafe materials in the cages and possible escape attempts (Bendow 382). However, when zoos take time to think about the animal's welfare, zoos can become a place of refuge. There are animals that are injured in the wild and are unable to survive on their own, but in the zoos they can live out the rest of their lives healthy and happy (McGaffin). In recent years, some zoos have chosen to move out some larger animals because they do not have the space available to provide an adequate enclosure for them (Lemonic, McDowell, and Bjerklie 50).
An issue with animal welfare in zoos is that best animal husbandry practices are often not completely known, especially for species that are only kept in a small number of zoos. To solve this organizations like EAZA and AZA have begun to develop husbandry manuals.
Many modern zoos attempt to improve animal welfare by providing more space and
Sometimes animals are unable to perform certain behaviors in zoos, like seasonal migration or traveling over large distances. Whether these behaviors are necessary for good welfare however is unclear. Some behaviors are seen as essential for an animal's welfare whilst others aren't. It is however shown that even in limited spaces, certain natural behaviors can still be performed. A study in 2014 for example found that Asian elephants in zoos covered similar or higher walking distances then sedentary wild populations. Migration in the wild can also be related to food scarcity or other unfavorable environmental problems. However a proper zoo enclosure never runs out of food or water, and in case of unfavorable temperatures or weather animals are provided with (indoor) shelter.
Animals in zoos can exhibit behaviors that are abnormal in their frequency, intensity, or would not normally be part of their behavioural repertoire. Whilst these types of behaviors can be a sign of bad welfare and stress, this isn't necessarily the case. Other measurements or behavioral research is advised before determining whether an animal performing stereotypical behavior is living in bad welfare or not. Examples of stereotypical behaviors are pacing, head-bobbing, obsessive grooming and feather-plucking A study examining data collected over four decades found that polar bears, lions, tigers and cheetahs can display stereotypical behaviors in many older exhibits. However they also noted that in more modern naturalistic exhibits, these behaviors could completely disappear. Elephants have also been recorded displaying stereotypical behaviours in the form of swaying back and forth, trunk swaying or route tracing. This has been observed in 54% of individuals in UK zoos. However it has been shown that modern facilities and modern husbandry can greatly decrease or even entirely remove abnormal behaviors. A study of a group of elephants in Planckendael showed that the older wild-caught animals displayed many stereotypical behaviors. These elephants had spent part of their lives either in a circus or in other substandard enclosures. On the other hand, the elephants born in the modern facilities that had lived in a herd their whole life barely displayed any stereotypical behaviors at all. The life history of an animal is thus extremely important when analyzing the causes of stereotypical behavior, as this can be a historical relict instead of a result of present-day husbandry.
Some zoos have used
The influence on a zoological environment on animal's longevity is not straightforward. A study of 50 mammal species found that 84% of them lived longer in zoos than they would in the wild on average. On the other hand, some research claims that elephants in Japanese zoos would live shorter than their wild counterparts at just 17 years. This has been refuted by other studies however. Such studies might not yet fully represent recent improvements in husbandry. For example, studies show that captive-bred elephants already have a lower mortality risk then wild-caught ones.
Climatic conditions can make it difficult to keep some animals in zoos in some locations. For example, Alaska Zoo had an elephant named Maggie. She was housed in a small, indoor enclosure because the outdoor temperature was too low.
Tsetse flies have invaded zoos that have been established in the tsetse zone. More concerning, tsetse-borne species of trypanosomes have entered zoos outside the traditional tsetse zone in infected animals imported and added to their collections. Whether these can be controlled depends on several factors: Vale 1998 found that the technique used in placing attractants was important; and Green 1988, Torr 1994, Torr et al. 1995, and Torr et al. 1997 found the availability for specifically needed attractants for the specific job to also vary widely.
Some critics and many animal rights activists claim that zoo animals are treated as voyeuristic objects, rather than living creatures, and often suffer due to the transition from being free and wild to captivity. However, ever since imports of wild-caught animals became more regulated by organizations like CITES and national laws zoos have started sustaining their populations via breeding. This change started around the 1970s. Many cooperations in the form of breeding programs have been set up since, for both common and endangered species. Emma Marris, writing an opinion piece for The New York Times, suggested zoos "stopped breeding all their animals, with the possible exception of any endangered species with a real chance of being released back into the wild ... Eventually, the only animals on display would be a few ancient holdovers from the old menageries, animals in active conservation breeding programs and perhaps a few rescues. Such zoos might even be merged with sanctuaries."
The examples and perspective in this section deal primarily with China and the United Kingdom and do not represent a worldwide view of the subject. (January 2022)
In some countries, feeding live vertebrates to zoo animals is illegal under most circumstances. The UK Animal Welfare Act of 2006, for example, states that prey must be killed for feeding, unless this threatens the health of the predator. Some zoos had already adopted such practices prior to the implementation of such policies. London Zoo, for example, stopped feeding live vertebrates in the 20th century, long before the Animal Welfare Act. Despite being illegal in China, some zoos have been found to still feed live vertebrates to their predators. In some parks like Xiongsen Bear and Tiger Mountain Village, live chickens and other livestock were found to be thrown into the enclosures of tigers and other predators. In Guilin, in south-east China, live cows and pigs are thrown to tigers to amuse visitors. Other Chinese parks like Shenzhen Safari Park have already stopped this practice after facing heavy criticism.
In the United States, any public animal exhibit must be licensed and inspected by the
Additionally, zoos in several countries may choose to pursue accreditation by the Association of Zoos and Aquariums (AZA), which originated in the U.S. To achieve accreditation, a zoo must pass an application and inspection process and meet or exceed the AZA's standards for animal health and welfare, fundraising, zoo staffing, and involvement in global conservation efforts. Inspection is performed by three experts (typically one veterinarian, one expert in animal care, and one expert in zoo management and operations) and then reviewed by a panel of twelve experts before accreditation is awarded. This accreditation process is repeated once every five years. The AZA estimates that there are approximately 2,400 animal exhibits operating under USDA license as of February 2007; fewer than 10% are accredited.
The European Union introduced a directive to strengthen the conservation role of zoos, making it a statutory requirement that they participate in conservation and education, and requiring all member states to set up systems for their licensing and inspection. Zoos are regulated in the UK by the Zoo Licensing Act of 1981, which came into effect in 1984. A zoo is defined as any "establishment where wild animals are kept for exhibition [...] to which members of the public have access, with or without charge for admission, seven or more days in any period of twelve consecutive months", excluding circuses and pet shops. The Act requires that all zoos be inspected and licensed, and that animals kept in enclosures are provided with a suitable environment in which they can express most normal behavior.
- List of zoos
- Wildlife refuge
- List of zoo associations
- Animals in captivity
- Virtual zoo
- Endangered species
- Zoo emergency response team
- Zoology (includes a list of prominent zoologists)
- Immersion exhibit
- Frozen zoo
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- Zoological Gardens keeping Asian Elephants
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