How Did Rabbits Get to Australia? The Story of an Invasion

The first rabbits: 1788 to the 1850s

Rabbits arrived with the First Fleet at Sydney in 1788 as farm animals for meat. For decades they were mostly kept in hutches and walled enclosures, and they do not seem to have spread widely on the mainland. Tasmania was different: by the 1820s, local reports already described rabbits running wild on some large estates in their thousands.

Several small releases took place in the 1850s, including on estates in South Australia. Some of these colonies stayed small for years, held back by predators, poor habitat or because the animals were tame domestic breeds poorly suited to life in the wild.

Thomas Austin’s release in 1859

The rabbit plague is usually traced to Thomas Austin of Barwon Park, near Winchelsea in Victoria. Austin had enjoyed shooting in England and wanted game animals to hunt in Australia. In 1859 his family in England sent him a shipment that included rabbits, usually given as about two dozen animals, which he released on his property.

Austin’s rabbits were at least partly wild-caught English rabbits rather than tame domestic ones, and they may have mixed with domestic stock. Hardy, wild-type rabbits were far better at surviving and breeding in the open, and that is one reason his release succeeded where others had not.

The results were dramatic. Within about ten years, rabbits were so common in Victoria that around two million could be shot or trapped each year with no noticeable effect on their numbers. It is often described as the fastest spread ever recorded for an introduced mammal.

Why rabbits spread so fast

Australia gave rabbits almost everything they needed:

• Mild winters, which allowed breeding almost all year.
• Open grassland and new pasture, created as settlers cleared land for sheep and cattle.
• Few predators able to cope with them at first. Many native predators had been reduced by settlers, and foxes, also brought from Europe, only became widespread later.
• Soft soils that were easy to burrow in, and the existing burrows of native animals.
• Huge breeding capacity. A European rabbit doe can breed from about three to four months old and raise several litters of 3–7 young a year.

From Victoria, the rabbit front pushed north and west across New South Wales, South Australia and Queensland. By the 1890s rabbits were approaching Western Australia, and today they occupy most of the southern and central parts of the continent, with scattered populations in the north.

The rabbit-proof fence

To stop rabbits moving west, Western Australia built a series of rabbit-proof fences between 1901 and 1907. The longest, the No. 1 Rabbit-Proof Fence, ran about 1,833 km (1,139 mi) from the north coast near Cape Keraudren to the south coast near Esperance. With two further fences, the system totaled about 3,256 km (2,023 mi).

The fences failed in their main purpose. Rabbits had already crossed the line in some places before construction finished, and they could dig under the netting, slip through damaged sections and open gates, or get past when floods and drifting sand broke the barrier. Much smaller fenced areas around farms and wildlife sanctuaries, by contrast, can keep rabbits out successfully.

Damage to land and wildlife

Rabbits are considered one of the most damaging invasive animals in Australia. Huge numbers stripped pastures, competing with sheep and cattle, and in drought they ate shrubs, seedlings and the bark of young trees. Bare ground left behind was easily eroded by wind and water, and the loss of topsoil can take centuries to recover.

Native wildlife suffered too. Rabbits compete with native plant-eaters for food and burrows, stop many native trees and shrubs from regenerating and support larger numbers of introduced foxes and cats, which also hunt native mammals. They are thought to have contributed to the decline of species such as the greater bilby. Australia’s government lists competition and land degradation by rabbits as a key threatening process for native species.

Disease and the rabbit population today

Before 1950 Australia was estimated to hold about 600 million rabbits. That year scientists released the myxoma virus, which causes myxomatosis, and the population crashed to around 100 million. Over the following decades rabbits became more resistant, and numbers rose again.

A second virus, rabbit hemorrhagic disease, escaped from a field trial on Wardang Island in South Australia in 1995 and killed millions more rabbits, especially in dry inland areas. A new strain, known as K5, was released in 2017. Rabbit numbers still rise after wet years and fall during droughts and outbreaks, and controlling them remains a long-term challenge.

Rabbits in other countries

Australia is the best-known case, but not the only one. European rabbits were introduced to New Zealand in the 19th century, where they became a serious problem in dry parts of the South Island. Settlers later released stoats and ferrets to control them, which proved devastating for native birds; see why stoats are a problem in New Zealand. Rabbits also spread through central Chile, Tierra del Fuego and Argentina, and onto more than 800 islands worldwide.

Australia faces several similar invasions by animals that settlers or officials released deliberately, from foxes to camels. The cane toad is another famous example; read why cane toads are a problem.

A pest in Australia, endangered at home

Ironically, the same species that overran Australia is declining in its native home. The European rabbit is listed as Endangered on the IUCN Red List because of steep losses in Spain, Portugal and southern France, where it is vital food for the Iberian lynx and Spanish imperial eagle. Find out more in Are rabbits endangered?