Located in Royal Park, the Melbourne Zoo receives over a million visitors per year. The enclosures, set in 55 acres (22 ha), are based on the animals' natural environment and arranged in bioclimatic zones to promote the objectives of the modern zoo: recreation, education, conservation and research. The butterfly house has a large research laboratory and is one of the more popular exhibits.
Melbourne Zoo has its roots in the 19th century and is the oldest surviving Australian zoo. It was typical of the many zoological gardens founded to emulate the success of the London Zoo. Its founding organisation, the Zoological Society of Victoria, was established in 1857 to promote animal husbandry, education and recreation. A small collection of birds, native animals and monkeys was gathered and housed in temporary enclosures in the Royal Botanic Gardens with the intention of providing permanent accommodation in Richmond Paddock on the north side of the Yarra River. Financial problems forced the Zoological Society into the hands of the government within a year of its foundation. Government Botanist Ferdinand von Mueller willingly took on the responsibility for managing the animals. He was also keen on promoting the importation of unusual domestic animals, thus paving the way for the society's conversion to the Acclimatisation Society of Victoria (ASV) in 1861.
A permanent home in Royal Park was laid out in 1861 to a classical design by Albert Lynch. Acclimatisation work absorbed the energies of the voluntary administrators, and little effort was made to attract visitors. When Albert Le Souef was appointed secretary of the ASV in 1870, he took on the challenge of developing the recreational aspect of the gardens and purchased some cheap exotic animals including lions, tigers, monkeys and bears. To reflect the shift in interest, the society's name was changed to the Zoological and Acclimatisation Society of Victoria.
The zoo experienced a boom period during the 1880s that firmly established it as a popular metropolitan recreational venue. On Sundays, when there was no entrance fee, the place was so crowded that police had to provide crowd control. Side shows, musical performances and camel and elephant rides were all part of the experience. In the early 20th century, the gardens matured and the range of exotic animals was extended to include giraffes, bison, zebras and hippos. The depression of the 1930s hit the zoo badly. With a severe lack of funds, and animals being kept in poor conditions, a power struggle emerged between those who wanted to develop the scientific side of the zoo through a substantial native fauna collection and those who wanted to build up the exotic collection. The supporters of the exotic collection won and, in the fallout, the Zoological and Acclimatisation Society relinquished control of the zoo to the newly established Zoological Board of Victoria (1937). But there was no significant development until the 1960s, when the zoo board began to modernise its enclosures and educational role. The Melbourne Zoo's large enclosures, beautiful gardens, organised activities and healthy evolution have transformed the 19th-century institution. Historical reminders are preserved in the main walk (1861) and the bar-and-brick orang-utan enclosure (1928).
In 1996 the management of the zoo was transferred to the Zoological Parks and Gardens Board (ZPGB). The ZPGB also manages Healesville Sanctuary and Victoria's Open Range Zoo at Werribee, the latter established in 1975 to display grassland animals and officially opened to visitors in 1983.