Edinburgh Zoo , formerly the Scottish National Zoological Park , is an 82-acre (33 ha) non-profit zoological park in Edinburgh, the capital of Scotland. The land lies on the south facing slopes of Corstorphine Hill, from which it provides extensive views of the city. Built in 1913, and owned by the Royal Zoological Society of Scotland, it receives over 600,000 visitors a year, which makes it Scotland's second most popular paid-for tourist attraction, after Edinburgh Castle.  As well as catering to tourists and locals, the zoo is involved in a large number of scientific pursuits, like captive breeding of endangered animals, researching into animal behaviour, and active participation in various conservation programs around the world. 
Edinburgh Zoo was the first zoo in the world to house and to breed penguins. It is additionally the only zoo in Britain to house koalas and giant pandas. The zoo is a member of the British and Irish Association of Zoos and Aquariums (BIAZA), the European Association of Zoos and Aquaria (EAZA), the World Association of Zoos and Aquariums (WAZA), and the Association of Scottish Visitor Attractions. It has additionally been granted four stars by the Scottish Tourism Board. The zoo gardens boast one of the most diverse tree collections in the Lothians. 
The Royal Zoological Society of Scotland (RZSS) was founded as a registered charity in 1909 by an Edinburgh lawyer, Thomas Hailing Gillespie. The Corstorphine Hill site was purchased by the Society with help from the Edinburgh Town Council in early 1913.  Gillespie's vision of what a zoological park should be was modelled after the 'open design' of Tierpark Hagenbeck in Hamburg, a zoo which promoted a more spacious and natural environment for the animals, and stood in stark contrast to the steel cages typical of the menageries built throughout the Victorian era.  The Scottish National Zoological Park was opened to the public in 1913 and was incorporated by Royal Charter later that year. In 1948, following a visit by His Majesty King George VI, the Society was granted the privilege of adding the prefix 'Royal' to its name. It remains the only zoo with a Royal Charter in the United Kingdom.
Edinburgh Zoo's long association with penguins began in January 1914, with the arrival of three king penguins from the Christian Salvesen whaling expedition which docked in Leith. The subsequent successful hatching of a king penguin chick in 1919 was the first penguin to be hatched in captivity. These were the first penguins to be seen outside of the South Atlantic anywhere in the world. The now famous daily penguin parade started by accident in 1950 with the escape of several birds. This proved so popular with visitors and the penguins that it is a daily feature of the zoo today.
In 1986, the Society acquired the Highland Wildlife Park at Kingussie, 30 miles (48 km) south of Inverness. The zoo and the park work together in providing the most appropriate captive habitat possible in Scotland. Public visitation trips between both sites are organised frequently by the RZSS. 
The zoo still retains the original charter, which drives its active breeding programme, and biodiversity, conservation and sustainability initiatives. The RZSS provides multiple ways for the public to help support its mission, including a membership club, animal adoption, donations, legacies and volunteering. 
Animals and exhibits
Named after the Budongo Forest in Uganda, the Budongo Trail facility houses a troop of 18 common chimpanzees ; 9 males (David, Louis, Qafzeh, Paul, Rene, Frek, Kindia, Liberius and Velu) and 9 females (Cindy, Pearl, Lucy, Eva, Sophie, Lianne, Heleen, Kilimi and Edith). The main building features viewing galleries, a lecture theatre and interactive games and displays designed to teach visitors about the chimpanzee's lifestyle and social structure. 
Edinburgh Zoo is well known for housing penguins in its collection, the first three being king penguins, which arrived in January 1913. The zoo's current penguin pool, named "Penguins Rock", is 65 metres long, 3.5 metres deep at its deepest point, contains 1.2 million litres of water, and houses colonies of gentoo, king, and rockhopper penguins. 
In 2011, Edinburgh Zoo leased two giant pandas, a male named Yáng Guāng (陽光, meaning "sunshine") and a female named Tián Tián (甜甜, meaning "sweetie"), from the Bifengxia Breeding Centre in China at a cost of $1m a year. The zoo spent £285,000 building an enclosure especially for the pandas, and they'll remain at the zoo for a maximum of ten years before being returned to China. Edinburgh Zoo is currently the only zoo in the United Kingdom that houses giant pandas.  
Opened in 2011, Brilliant Birds is a walk-through aviary housing several species of exotic birds, including Nicobar pigeons, Bali starlings, lilac-breasted rollers, chestnut-backed thrush, and Victoria crowned pigeons. A selection of amphibians, invertebrates and fish are additionally displayed in the building's main entrance hall, including axolotl, blue poison dart frogs, mudskippers, figure 8 pufferfish, banded archerfish, blind cave fish, and a colony of leafcutter ants. 
Koala Territory was first opened in 2005, and houses four koalas, three males named Gooanroo, Yabbra and Yooranah, and a female named Alinga. Yooranah is the offspring of Alinga and Goonaroo, and was born in 2013. Koala Territory is decorated with Aboriginal-inspired artwork, and features a garden of eucalyptus plants. 
Opened in 2015, the walkthrough became the zoo's swamp wallabies new home. Visitors can get up close to these marsupials.
A daily show in which keepers demonstrate the natural skills of animals to an audience of visitors. Keepers use positive reinforcement training with every animal, which means that the animals that perform in the shows are never forced into doing tricks.  Because of this, the animals used in Animal Antics vary between shows.
Other notable mammal species in the zoo's collection include oriental small-clawed otters, Asian lions, meerkats, sun bears, Sumatran tigers, giant anteaters, binturong, African wild dogs, Grévy's zebras, greater one-horned rhinoceros, banteng, red river hogs, North American porcupines, swamp wallabies, pygmy hippopotamus, Scottish wild cats, Malayan tapirs, white-faced saki monkeys, ring-tailed lemurs, cottontop tamarins, geladas, and Barbary macaques.
Other notable bird species in the zoo's collection include Darwin's rhea, Chilean flamingos, Egyptian vultures, eastern white pelicans, scarlet ibis, waldrapp ibis, great argus pheasants, ocellated turkeys, red-fronted macaws, rainbow lorikeets, hamerkop, and southern cassowary.
Several of the zoo's animals have held military rank.
- Wojtek was a bear adopted in Iran by the Polish II Corps and enlisted into the twenty-second Artillery Supply Company to allow him to travel when the troops were posted. He served in the Middle East and throughout the Battle of Monte Cassino and retired to Edinburgh Zoo when the Polish troops, billeted in Scotland, demobilised. 
- Sir Nils Olav, a king penguin, was the mascot and Colonel-in-Chief of the Norwegian King's Guard. He was adopted in 1972 when the King's Guard were in the city for the Edinburgh Military Tattoo, given the rank of visekorporal (lance corporal), and promoted each time the corps visited the city. He died in 1987 and his successor, Nils Olav II, inherited his rank.  Nils was visited by the Norwegian King's Guard on 15 August 2008 and awarded a knighthood. The honour was approved by the King of Norway, King Harald V. During the ceremony a crowd of several hundred people joined the 130 guardsmen at the zoo to hear a citation from King Harald the Fifth of Norway read out, which described Nils as a penguin "in every way qualified to receive the honour and dignity of knighthood". 
The carnivore rock dens, located between the Sumatran tigers and the geladas are to be totally overhauled, with the Amur leopard and jaguar leaving the collection. The Asian lion, Sumatran tiger and Scottish wildcat will remain on-show.  A new Sumatran tiger enclosure is being developed in the meadow behind the current enclosure. Red panda are due to rejoin the collection later in the year.
Research and conservation
Edinburgh Zoo is the national centre for primate behavioural research. Budongo Trail , a state-of-the-art chimpanzee enclosure, was opened in May 2008 by The Princess Royal. Budongo Trail is a naturalistic enclosure which can house up to 40 chimps. It includes a large outdoor area and three separate indoor areas for the chimps together with observation areas and a lecture theatre for the public. The RZSS is the principal sponsor in the long term study and conservation of a group of approximately 60 chimpanzees as part of the Budongo Conservation Field Station in Uganda, Africa.  Amidst the opening of Budongo Trail, Jane Goodall described it as a "wonderful facility" where primates "are probably better off [than] living in the wild in an area like Budongo [Forest], where one in six gets caught in a wire snare, and countries like Congo, where chimpanzees, monkeys and gorillas are shot for food commercially." 
In addition to Budongo Trail, the zoo is home to Living Links , a field station and research centre for the study of primates that was developed in a partnership with the University of St Andrews. Living Links houses capuchin monkeys and squirrel monkeys originating from the forests of South America, and offers researchers unique opportunities to study primate behaviour. 
In July 2006, a cull of invasive brown rats on the Scottish island of Canna was deemed a provisional success  and after two years of observation, throughout which time no rats were observed, the island was declared officially rat free by the Environment Minister, Mike Russell on 7 June 2008.  The rats had been outcompeting the rare local wood mouse, known as the Canna mouse and additionally endangering local seabird populations. The National Trust for Scotland which own the island invested £500,000 employing exterminators from New Zealand to cull the estimated 10,000 brown rats. in co-operation with RZSS, approximately 150 Canna mice were captured and homed at Edinburgh Zoo and the Highland Wildlife Park. 40 mice were returned to the island in late 2006 with the remaining being re-introduced in stages. 
In May 2008, a joint application submitted by the Royal Zoological Society of Scotland (RZSS) and the Scottish Wildlife Trust (SWT) was approved by the Scottish Government allowing for a trial reintroduction of the European beaver to the Knapdale Forest in Mid- Argyll. If the trial is successful then the European beaver will be the first mammal to be reintroduced to the United Kingdom. Beavers have been extinct in Scotland after the sixteenth century, when they were hunted for their pelt, meat and medicinal properties (use of castoreum). 
Before being acquired by the society, the Corstorphine hill site was a nursery, once owned by Thomas Blaikie, who planted a large number of of the great French parks like ‘La Bagatelle’. On this site two nurserymen raised the famous apple cultivars ‘John Downie’ and ‘James Grieve’. Today, the zoo has one of the most diverse tree collections in the Lothians with 120 species. The south-facing aspect allows bananas to be grown outside. Increasingly, horticulture is seen as a discipline in its own right, with the focus on habitat creation within enclosures, food stuffs for the animals, and enrichment for both the animals and the visiting public. 
Organisations that remain critical of Edinburgh Zoo's work include the Animal Liberation Front, who have voiced their distaste for the quality of the enclosure that formerly housed polar bears.  The Born Free Foundation has additionally stated several times that the zoo fails in its conservation work,  as well as opposing the zoo's plans to house elephants. 
Edinburgh Zoo received a public backlash on Twitter after the European Endangered Species Programme (EEP) recommended that they should cull three red river hog piglets after an unplanned birth. A protest took place under the #savethehogs tag on Thursday 3 February 2011.  The Twitter campaign was started by OneKind, with major support from Captive Animals Protection Society. On Friday 4 February 2011, it was announced that the #savethehogs campaign had been successful and the zoo would attempt to re-home the piglets. 
Following various internal issues and allegations relating to senior staff, the zoo was subject to investigations relating to its charitable status. The Office of the Scottish Charity Regulator (OSCR) held an inquiry into the Royal Zoological Society of Scotland, and one director was fired while two others were suspended.   The zoo suspended its chief operating officer and acting chief executive Gary Wilson while it investigated allegations made against him. 
The zoo additionally came under criticism for plans to charge £20 per person for visitors to watch the necropsy of an animal.  A OneKind spokesman criticised the idea, largely due to the timing of the event, which was scheduled to take place two months after the zoo announced a £2 million loss in profits, making the necropsy seem like a "Money-making drive". 
In February 2012, the zoo was told to conduct a full review of its financial controls following an inquiry into complaints about how the zoo was run in 2011. The report by the OSCR cleared the zoo of misconduct but found "areas of governance that can be improved". 
In May 2012, several hundred zoo visitors were forced to seek shelter after a family of hogs escaped from keepers and ran amok. Those who had taken refuge in the monkey house later described scenes where zoo workers pursued the animals with various equipment including brushes and dart guns. Though the drama lasted over an hour, the adult hogs were recaptured unharmed. 
On 22 August 2012 a scarlet ibis escaped from the zoo and went on the loose in the city after a squirrel had chewed a hole in the netting at the top of its cage. Keepers noticed it was missing and later that day it was spotted more than 3 miles away in Dundas Street, near the city centre.  The ibis was missing for nearly a week before being recaptured four miles from the zoo. 
In September 2012 zoo customers were herded indoors when a Heck bull escaped from its enclosure. The 600 kg animal with three feet long horns was loose for over 40 minutes, until zoo workers and vets managed to restrain him by using tranquilliser darts.