The story of the European rabbit (Oryctolagus cuniculus) in Australia is one of the most dramatic examples of ecological invasion in recorded history. What began with the release of just 24 wild rabbits on a single Victorian property in 1859 quickly spiralled into a biological catastrophe of continental proportions. Within decades, rabbits had spread across the entire southern half of Australia, consuming native vegetation, degrading soil, and driving countless native species towards extinction. Today, despite more than a century of intensive control efforts, rabbits remain one of Australia’s most damaging invasive species, costing the nation billions of dollars in agricultural losses and ecological damage.
The Release at Barwon Park
In October 1859, Thomas Austin, a wealthy pastoralist and keen sportsman, released 24 wild rabbits on his property, Barwon Park, near Winchelsea in Victoria. Austin, who had emigrated from England, yearned for the recreational hunting he had enjoyed in his homeland and believed that a small population of rabbits would provide excellent sport. He reportedly declared that the introduction of a few rabbits could do little harm and might provide a touch of home in addition to some hunting opportunities.
Austin’s prediction could not have been more spectacularly wrong. The mild Australian climate, abundant grasslands, and absence of natural predators created ideal conditions for rabbit reproduction. Rabbits can breed from as young as four months of age, and a single pair can produce up to 40 offspring per year. Within just six years of Austin’s release, the rabbit population at Barwon Park had grown so large that 20,000 rabbits could be shot or trapped annually without any noticeable impact on the overall population.
From Victoria, rabbits spread at an estimated rate of 130 kilometres per year, one of the fastest rates of colonisation ever recorded for a mammal. By the 1880s, they had crossed into New South Wales and South Australia. By the turn of the century, they had reached Queensland and Western Australia. At their peak, the Australian rabbit population was estimated at around 10 billion individuals — approximately 1,300 rabbits for every person in Australia at the time.
Environmental Devastation
The environmental impact of rabbits on the Australian landscape has been profound and far-reaching. Rabbits are voracious herbivores that consume a wide variety of native grasses, shrubs, and seedlings. In semi-arid and arid regions, where vegetation is sparse and slow to recover, rabbit grazing has transformed once-productive landscapes into barren, eroded wastelands.
By stripping vegetation from the soil surface, rabbits have accelerated soil erosion across vast areas of the Australian interior. Without the protection of ground cover, topsoil is vulnerable to wind and water erosion, leading to the formation of gullies, the loss of fertile soil, and the degradation of waterways through increased sedimentation. Research by CSIRO has estimated that rabbit-induced soil erosion costs Australia hundreds of millions of dollars annually in lost agricultural productivity.
The impact on native biodiversity has been equally severe. By competing with native herbivores for food and preventing the regeneration of native plant species, rabbits have fundamentally altered the structure and composition of Australian ecosystems. Numerous native plant species have been pushed to the brink of extinction by rabbit grazing, and the cascade effects through food webs have impacted a wide range of native animal species.
Rabbits have also been a significant factor in the decline of small native mammals. By degrading ground cover, rabbits reduce the availability of shelter for species such as bilbies, bandicoots, and small wallabies, leaving them more exposed to predation by foxes and cats. Additionally, the abundant food supply provided by rabbits has supported larger populations of these introduced predators, further increasing the pressure on native prey species.
The Rabbit-Proof Fence
One of Australia’s earliest and most ambitious attempts to control the spread of rabbits was the construction of the rabbit-proof fence in Western Australia. Built between 1901 and 1907, the fence stretched for 3,256 kilometres from the coast near Esperance in the south to the coast near Port Hedland in the north, making it the longest unbroken fence in the world at the time.
The fence was designed to prevent rabbits from spreading into the pastoral lands of western Western Australia. However, by the time the fence was completed, rabbits had already penetrated beyond the barrier in several locations. While the fence did slow the westward advance of rabbits and provided some protection to agricultural lands on its western side, it ultimately failed to halt the spread of the invasion. The fence remains standing today and continues to serve as a barrier against emus and other pest animals, but its original purpose as a rabbit barrier has long since been superseded by more modern control methods.
Biological Control: Myxomatosis and Calicivirus
Australia’s most significant successes in rabbit control have come through the use of biological control agents. In 1950, the myxoma virus was deliberately released into the rabbit population, causing the disease myxomatosis. The initial impact was dramatic — the virus killed an estimated 99 per cent of infected rabbits in some areas, reducing the national population from an estimated 600 million to around 100 million within just two years.
However, the effectiveness of myxomatosis gradually declined as rabbits developed genetic resistance to the virus and the virus itself evolved to become less virulent. By the 1990s, rabbit populations had recovered to approximately 300 million, prompting the search for a new biological control agent.
In 1996, rabbit haemorrhagic disease virus (RHDV), also known as rabbit calicivirus, was accidentally released from a research facility on Wardang Island in South Australia. Despite the unplanned nature of the release, the virus spread rapidly through mainland rabbit populations, reducing numbers by an estimated 65 per cent in arid and semi-arid regions. The virus was subsequently officially released as a biological control agent and has been complemented by the release of a new strain, RHDV2 or K5, in 2017.
The Invasive Species Council and the CSIRO continue to research new strains and approaches to biological control of rabbits, recognising that ongoing evolution of resistance in rabbit populations requires a continual pipeline of new control tools. The combined use of myxomatosis, RHDV, and conventional control methods such as warren destruction, fumigation, and baiting remains the foundation of rabbit management in Australia.
Economic Costs
The economic impact of rabbits on Australian agriculture and the environment is staggering. A comprehensive assessment published by the CSIRO estimated that rabbits cost the Australian economy approximately $206 million per year in lost agricultural production alone. When environmental costs such as soil erosion, loss of biodiversity, and degradation of waterways are included, the total economic impact is estimated to exceed $1 billion annually.
Rabbits compete directly with livestock for pasture, and in drought years this competition can be particularly intense. In some regions, farmers have reported that rabbit grazing consumes up to 50 per cent of available pasture, significantly reducing the carrying capacity of the land for sheep and cattle. The costs of rabbit control — including baiting, fumigation, warren ripping, and fencing — add a further financial burden to already stretched agricultural operations.
Recovery and Hope
Despite the enormous challenges posed by feral rabbits, there are grounds for cautious optimism. In areas where rabbit populations have been effectively suppressed through integrated control programmes, native vegetation has shown remarkable powers of recovery. Landscapes that had been stripped bare by decades of rabbit grazing have regenerated with native grasses, wildflowers, and shrubs, providing habitat for native animals and stabilising fragile soils.
The ongoing development of new biological control agents, combined with improvements in conventional control methods and greater coordination between landholders, conservation agencies, and researchers, offers hope for more effective rabbit management in the future. The rabbit will likely never be eradicated from Australia, but with sustained effort and investment, it is possible to reduce its populations to levels that allow native ecosystems to recover and thrive.
The story of the rabbit in Australia is a powerful illustration of the catastrophic consequences that can follow the thoughtless introduction of a species into a new environment. It serves as an enduring lesson for biosecurity policy and a reminder that the protection of Australia’s unique natural heritage requires constant vigilance and a willingness to invest in long-term environmental management.