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Rabbit numbers are booming, but unlike three previous plagues of the marauding pests since the 1950s, Australia does not have a virus it can release to rein in the exploding numbers, a leading cause of environmental damage and agricultural losses.
Steady rainfall over the past two years has fuelled growth of the vegetation rabbits need to breed their litters.
Rabbit populations are booming in rural and urban areas.
Rabbits can birth litters as often as once a month, and as those surviving kits mature and start breeding, it triggers the kind of exponential growth that creates populations so vast and widespread that experts warn devastating ecological damage is inevitable.
Rabbits change entire landscapes by eating all the green vegetation and outcompeting native animals for food, digging burrows that cause soil erosion and damage waterways. The federal government has calculated rabbits cause about $250 million in lost agricultural production a year.
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Since 1950, Australia has deployed three viruses deadly to rabbits, known as a biocontrol, to quickly cut rabbit numbers. It typically takes the rabbit population about 10 years to adapt to the disease and after that, numbers start to rise once more.
The most recent biocontrol, a strain of calicivirus, was released in 2017.
Centre for Invasive Species Solutions national rabbit coordinator Heidi Kleinert says: “We are seeing a boom in populations in locations spread across the country.”
She says rabbits are flourishing in farming areas and outer suburban areas as well.
“Their population growth is being driven by the food available, given rabbits are triggered to breed by regular growth of green vegetation that has been available for some time now,” Kleinert says.
Australia’s top science agency the CSIRO released the world’s first vertebrate pest biocontrol in 1950, in a desperate bid to quell the rabbit plague.
That virus, known as myxomatosis or myxo, was extremely effective and killed around 99.8 per cent of infected rabbits and it took until the 1990s for rabbits to adapt and breed again in plague-like proportions.
Since then, two strains of the calicivirus have been released into the wild, in 1995 and 2017, both of which cut rabbit numbers dramatically. But each time rabbits bounced back. Now, due to lack of funding, there is no deadly virus ready to release into the wild and scientists say that there is not enough funding to develop the next biocontrol for rabbits.
Invasive Species Council chief executive Jack Gough says funding a new rabbit virus must be a national priority.
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“The government will be judged on what they funded today, when they know this is about to get worse. We’re concerned that some complacency has crept into decision-making because rabbit numbers have been low,” Gough says.
Biocontrols take years or decades to develop and funding for the programs that developed them for rabbits, the Rabbit Biocontrol Pipeline Strategy, ceased in 2022 and the Investment in Genetic Biocontrol of Vertebrate Pests ran out of money in 2025.
The Albanese government has committed $1.5 million to extend biocontrol research, but this will be exhausted by June next year and there is no prospect of a new biocontrol without more funding to extend the work for many years to come.
“We don’t have a good model nationally in terms of how to fund biocontrol. It requires long-term investment, which needs a long-term commitment,” says Centre for Invasive Species Solutions director of research and development John Virtue.
He says he’s been alarmed at the proliferation of rabbits in the Riverland irrigation district in his home state South Australia, despite recent dry conditions.
“The lack of long-term funding for biocontrol is a critical risk for Australia.”
Agriculture Minister Julie Collins did not respond directly to questions about federal government funding shortfalls, but emphasised development of new biocontrols was a joint responsibility with states and says the Albanese government has committed $1.2 million to control measures like digging up rabbit warrens as well as fencing, shooting and trapping.
“The Australian government will continue working with state and territory governments, which are primarily responsible for on-ground management of invasive species, to help protect Australia’s environment and agriculture,” Collins says.
CSIRO senior principal research scientist in rabbit biocontrol Tanja Strive says it would be an “absolute disaster” if Australia was unable to release another biocontrol targeting rabbits.
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“We need the next virus right about now because the last successful one was 10 years ago,” Strive says.
“The last virus has been really good at keeping numbers relatively low for about the last 10 years. For eight of those years we actually have data that show that it’s kept them quite stable. It knocked rabbits down by 60 per cent and held them there for at least eight years.”
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