Rabbits arrived in Australia with the very first European settlers. Five domestic rabbits came ashore in Sydney with the First Fleet in 1788, brought as livestock. But those tame animals weren’t the ones that triggered the ecological catastrophe Australia is still dealing with today. That distinction belongs to a single shipment of wild rabbits released on a private estate in 1859, an event that launched one of the fastest and most destructive biological invasions in recorded history.
The First Fleet Brought Domestic Rabbits in 1788
When the British established their first colony at Sydney, the fleet carried a small inventory of livestock that included five domestic rabbits. These animals were kept for food, and for decades, domestic rabbits remained just that: penned farm animals scattered across early settlements. They didn’t establish wild populations. Genetic analysis of rabbit remains from the Sydney area confirms they were predominantly domestic breeds, not wild European rabbits. For roughly 70 years, rabbits in Australia stayed contained and unremarkable.
Thomas Austin’s 1859 Release Changed Everything
The turning point came on Christmas Day 1859, when a wealthy landowner named Thomas Austin hosted a hunting party at his estate, Barwon Park, near Geelong in Victoria. Austin had imported 25 wild rabbits from England, along with partridge and hare, to stock his property as game for sport shooting. Wild European rabbits are a fundamentally different animal from the docile domestic breeds that had been in Australia for decades. They’re faster breeders, more adaptable, and far better at surviving in open landscapes.
A 2022 genomic study published in the Proceedings of the National Academy of Sciences confirmed what historians had long suspected: this single introduction of wild rabbits at Barwon Park triggered the biological invasion. The DNA of feral rabbits across the continent traces back to that release, not to the earlier domestic populations in Sydney or other settlements.
How They Spread Across a Continent
The speed of the rabbit expansion was staggering. In wet, forested country, they pushed outward at 10 to 15 kilometers per year. In the open rangelands, they covered more than 100 kilometers per year. Within 50 years of Austin’s release, rabbits had colonized much of the continent. Australia’s warm climate, vast grasslands, and lack of natural predators capable of controlling them created nearly ideal conditions. A single pair of rabbits can produce multiple litters per year, with each litter containing four to eight young that themselves begin breeding within months.
Today, feral rabbits occupy roughly 70 percent of Australia’s landmass. The most recent population estimate sits at around 200 million animals.
The Rabbit-Proof Fence That Didn’t Work
One of the earliest and most ambitious attempts to stop the spread was purely physical. Between 1901 and 1907, Western Australia constructed what became known as the Rabbit-Proof Fence, a barrier stretching 3,256 kilometers (just over 2,000 miles) across the state. It was designed to block the westbound advance of rabbits into agricultural land. The project was enormous and expensive, but it failed. Rabbits had already crossed the fence line before construction was finished in some sections, and maintaining an unbroken barrier across thousands of kilometers of remote terrain proved impossible.
Ecological Damage to Native Species
Rabbits don’t just eat grass. They strip landscapes down to bare soil, consuming native seedlings, shrubs, and ground cover that native animals depend on for food and shelter. Australia’s Department of Climate Change, Energy, the Environment and Water reports that feral rabbits likely caused the extinction of several small ground-dwelling mammals in the arid interior, species weighing up to about 5.5 kilograms that couldn’t compete for food or habitat. On Philip Island in the Norfolk Island group, rabbits and goats together reduced the island to exposed bedrock, driving at least two plant species to local extinction. Rabbits even threaten seabird colonies, including Gould’s petrel, by destabilizing nesting habitat through burrowing and overgrazing.
The economic toll is also significant. Feral rabbits cost Australian agriculture and horticulture an estimated $217 million per year through crop damage, pasture degradation, and the expense of control programs.
Biological Weapons: Myxomatosis
By the mid-20th century, Australia turned to biological control. In 1950, scientists released the myxoma virus, which causes the disease myxomatosis, into the wild rabbit population in southeastern Australia. The initial results were devastating to the rabbits. More than 99 percent of infected animals died during 1950 and 1951. It was one of the most dramatic pest control successes ever recorded.
But evolution works fast in a species that breeds as rapidly as rabbits do. Resistance to the virus increased sharply in the first decade after release, between 1950 and 1960. The rate of genetic adaptation then plateaued for 10 to 15 years before climbing again in the mid-1970s, coinciding with the introduction of European rabbit fleas as a new transmission vector for the virus. The fleas were supposed to make the virus spread more effectively, and they did, but they also created new selection pressure that drove resistance even higher. By the 1990s, populations of highly resistant rabbits were common across Australia, and myxomatosis alone could no longer keep numbers in check.
A Second Virus: Rabbit Hemorrhagic Disease
Australia’s next biological weapon arrived in the mid-1990s. Rabbit hemorrhagic disease virus (known as RHDV) became established in 1995 after escaping from a research facility on Wardang Island, off the coast of South Australia, where it was being tested. By October 1996, the South Australian government officially authorized its release for rabbit control under its Biological Control Act.
The initial impact varied by region. In arid areas, where rabbits had fewer places to hide and conditions favored the virus, populations dropped by up to 95 percent. Across different outbreaks, mortality among infected rabbits ranged from 45 to 80 percent. A newer strain, RHDV2, was first confirmed in Australian rabbits in 2016 and has since become the dominant circulating virus. It proved capable of overcoming the antibody protection rabbits had built up against the original strain, driving further population declines at monitored sites.
A third variant called K5 was deliberately released as a supplementary control measure, but monitoring through community sampling and the national RabbitScan reporting system showed it had minimal additional impact.
Why the Problem Persists
Despite more than 70 years of biological control efforts, physical barriers, and conventional methods like poisoning and warren destruction, Australia still has around 200 million feral rabbits. The pattern keeps repeating: a new control measure delivers a sharp initial reduction, natural selection favors the survivors with genetic resistance, and the population rebounds. The virus weakens over generations too, as less lethal strains outcompete highly virulent ones by keeping their hosts alive long enough to spread further.
All of this traces back to a single decision by one landowner who wanted something to shoot on Christmas Day in 1859. Thomas Austin reportedly said that introducing a few rabbits “could do little harm and might provide a touch of home.” It became one of the most consequential ecological mistakes in modern history.