Australia has fought many wars, but one of the longest has been against an enemy weighing about two kilograms, armed with nothing more formidable than teeth and an extraordinary capacity to reproduce.
The rabbit wars may be starting again. Reports from around Australia suggest rabbit populations are increasing substantially. In the South Australian town of Willalooka, residents report seeing rabbits outside their homes in the morning and scores of them while driving at night. In Victoria, rabbits have damaged sporting grounds and market gardens. In Junee in New South Wales, rabbits burrowing around graves became such a problem that the local cemetery had to be closed temporarily while authorities dealt with them.
The latest estimate cited by The Saturday Paper puts Australia's wild rabbit population at around 200 million. That number should make Australians nervous because we have seen this before.
The European rabbit was introduced into Australia in the nineteenth century, with the famous release by Thomas Austin near Geelong in 1859 helping establish the population that subsequently exploded across the continent. Within decades, rabbits had accomplished one of the fastest mammalian invasions ever recorded.
Australia was almost perfect rabbit country. There was abundant food, relatively favourable climate across enormous areas and initially few effective natural controls. Rabbits did what rabbits famously do. They bred. And bred. And bred some more.
The ecological consequences were enormous. Rabbits stripped vegetation, competed with native animals, damaged agricultural land and prevented regeneration of trees and shrubs. Their warrens contributed to erosion. Farmers poisoned, trapped and shot them. Governments constructed enormous rabbit-proof fences.
Still they came. Eventually Australia turned to biological warfare. Myxomatosis was released in 1950 and produced one of the great successes in the history of biological pest control. Rabbit populations crashed by more than 90 per cent in many areas. For farmers who had watched rabbits consume their livelihoods, it must have seemed almost miraculous.
But evolution had not signed the peace treaty. Rabbits with greater resistance survived and reproduced, while evolutionary pressures also affected the virus. Rabbit numbers began recovering.
Australia therefore deployed another biological weapon. Rabbit haemorrhagic disease virus, commonly called calicivirus, was officially released in 1996. Once again the results were spectacular. In some environments rabbit populations were devastated. Once again, however, evolution continued.
CSIRO now warns that rabbit populations have developed increasing resistance to some biological controls. A newer strain, RHDV2, appeared in Australia around 2014–15 and rapidly became dominant. It initially produced another substantial decline in wild rabbit numbers.
But there is an ominous pattern here. CSIRO researchers say the effectiveness of rabbit biological controls has historically begun declining after approximately 10 to 15 years. Count forward from the arrival of RHDV2 and Australia is now sitting almost exactly in that danger zone.
The rabbits may be coming back. This should not surprise anybody familiar with evolutionary biology. Biological control creates an enormous selection pressure. A virus sweeps through a rabbit population and kills susceptible animals. Rabbits possessing characteristics that give them greater resistance have a better chance of surviving and reproducing.
Generation after generation, natural selection does its work. Unfortunately, governments operate on political cycles rather than evolutionary ones. When rabbits are everywhere, governments become interested in rabbits. Money flows into research and control programs. Scientists develop new biological weapons. Farmers undertake eradication campaigns. Rabbit populations collapse. Then everybody forgets about them.
That appears to be part of the present problem. Federal funding for the national Rabbit Biocontrol Pipeline Strategy ended in 2022. The federal government has continued providing some funding for CSIRO rabbit-control research, but researchers and invasive-species organisations argue that considerably more is required to maintain the pipeline of future biological controls.
This is not something that can be fixed six months after somebody notices rabbits covering the countryside. Developing a new biological control is understandably slow. Scientists must identify promising viral variants, determine whether they are sufficiently effective, establish that they will not create unacceptable risks to other species, navigate regulatory processes and then work out how to deploy them.
CSIRO's Dr Tanja Strive estimates that getting a new viral candidate through this process can take eight to ten years. That is why complacency is so dangerous. If Australia waits until rabbit numbers have exploded before seriously funding the next generation of controls, we have already lost years.
Traditional control methods remain important. Farmers can destroy warrens, use approved baits and employ other established methods. In suitable circumstances rabbits can also be shot. But there is a brutal mathematical problem. Rabbits reproduce too quickly.
According to figures cited in The Saturday Paper, under ideal breeding conditions rabbits can reproduce every 28 days. The article gives the striking illustration that two rabbits could theoretically become 184 within 18 months.
This is why local eradication can become an endless battle. A farmer can spend considerable money eliminating rabbits from his property only to have animals move back from neighbouring land.
Urban Australia presents an even stranger battlefield. You cannot casually undertake large-scale baiting around suburban pets. You cannot rip apart an athletics field to destroy every warren without consequences. Shooting rabbits in suburban backyards is obviously not a practical general solution.
Biological control therefore remains one of Australia's most powerful weapons. There is also a larger environmental irony here. Australia spends enormous sums discussing threats to native biodiversity while sometimes neglecting one of the oldest and best-established threats already hopping around the landscape.
Rabbits do not merely eat farmers' crops. They compete with native animals for food and shelter, destroy seedlings and prevent regeneration. Even relatively small rabbit populations can profoundly alter vegetation.
Australia therefore cannot afford to regard rabbit control as some quaint historical struggle belonging to sepia photographs of farmers standing beside mountains of rabbit carcasses. The rabbit war never actually ended. Australia merely won several spectacular battles. Myxomatosis won one. Calicivirus won another. RHDV2 gave us another period of relief. Each time biological control knocked rabbit populations backwards, evolutionary pressure began preparing the next counterattack.
There is something alarming about the rabbit's persistence. We imported it into one of the world's most unusual ecosystems, constructed thousands of kilometres of fencing against it, poisoned it, shot it, destroyed its warrens and unleashed multiple viruses upon it. And still the rabbit is here.
The lesson should be obvious. Australia needs a permanent rabbit-control research program rather than periodically rediscovering the problem after populations explode. Biological control needs to be treated as an arms race in which the opposing side never stops evolving merely because government funding has stopped.
Scientists are already looking for new viral variants, while more futuristic genetic approaches may eventually offer additional possibilities. But those technologies require years of research and careful safety assessment.
The immediate task is therefore much less glamorous: maintain the research pipeline, monitor rabbit populations properly and act before exponential reproduction turns a manageable problem into another national plague.
Australia has been fighting the rabbit for more than 150 years. We should have learnt one thing by now. Whenever we think we have finally won, the rabbits are already preparing the next round. While some urban liberals may find bunnies cute, they are a deadly menace to farming.
https://archive.is/20260413174041/https://www.thesaturdaypaper.com.au/news/environment/2026/04/04/australia-once-again-losing-the-rabbit-war#selection-993.19-993.67