It closed in August 2003 after running up a debt of around £3.5 million and failing to renew its zookeeper licence, having been unable to meet new standards on animal welfare.

[4] The initial proposal was for the zoo to be in Bellahouston Park in 1938, beginning with a four-acre enclosure with expansion as the project went on.

At the end of 1938 the Society looked at the Calderpark Estate, two miles beyond the city boundary with a large plot of land available for construction and free-animal enclosures.

The property had formerly been farmed by Cistercians, and the original mansion had been demolished a decade earlier when it became unsafe due to subsidence from underground coal mines.

[4] When construction began during Britain's recovery period, many of the zoo's buildings were made from old war materials such as the enclosures being built out of concrete roadblocks (designed to hinder tank movements on the chance of invasion), bricks from demolished air raid shelters, and metal from now defunct battleships.

At the time the prize exhibits were the lions and a rare white peacock – now fairly common – which attracted many people to the zoo, some bringing their own exotic pets to add to the zoo's already expanding collection: these included monkeys, parrots and many other rarer species.

Starting in 1999 the zoo tried to sell off its excess to land, but delays in planning permission prevented the sale.

[16] Since the closure of the zoo in 2003, the area and old buildings fell into disrepair with many of the enclosures being burned, demolished or vandalised as well as illegal dumping from nearby developers and constructors causing further damage to the structures to the point where many were unsafe for use.

Birds on display at the zoo included golden eagle, lorikeets, scarlet macaws, and Indian peacocks.

[18] During the zoo's final years before closure, it developed a large debt due to dwindling visitor numbers, lack of public funding, and the death of Richard O’Grady, the zoo's director, in 2001, which led to poor management decisions and negligence.

A report written by Jordi Casamitjana, for Advocates for Animals, made multiple claims of animal cruelty, including that unwanted pets were killed and fed to the zoo's snakes, and that the parents of the lion cubs at the park were brother and sister.

[20] Samantha Scott, an animal behaviourist at the Royal (Dick) School of Veterinary Studies, also commented in the report about the mental state of Glasgow zoo's animals: "The White rhino showing signs of possible stereotypic behaviour (circling), which is normally associated with difficulties in coping with captive life, or frustrated territorial patrolling.