Sydney’s rat problem has just levelled up—and not in a good way. If you’ve noticed more furry visitors scurrying around your backyard or heard the telltale scratching in your walls, you’re not alone.
New research has revealed that a plague of so-called ‘super rats’ is sweeping through Sydney and other major Australian cities, and these rodents are becoming nearly impossible to kill with traditional poisons.
But what’s really going on, and what does it mean for your home, your health, and our native wildlife?
The rise of the mutant rat
It sounds like something out of a horror film, but the science is real.
A team led by Alicia Gorbould, a PhD student and environmental toxicologist at Edith Cowan University, has discovered that more than half of the black rats tested in Sydney, Melbourne, Perth, and Brisbane between 2021 and 2024 carry a genetic mutation.
This mutation makes them resistant to the most commonly used rat poisons, specifically second-generation anticoagulant rodenticides (SGARs).
The mutation, known as Tyr25Phe, was found in a staggering 80 per cent of black rats in Perth, 45 per cent in Sydney, and 39 per cent in Melbourne.
Brisbane, for now, seems to have dodged the bullet, with none of the 10 rats tested showing the mutation. But the trend is clear: our rats are evolving, and fast.
Why should we care?
At first glance, you might think, ‘So what? Rats have always been a problem.’ But this new breed of super rat is more than just a household nuisance. The real danger lies in the way we’re trying to fight them.
As these rats become resistant to poisons, people are using more and more toxic bait in a desperate attempt to get rid of them.
Not only is this approach largely ineffective, but it’s also creating a dangerous cycle: the more poison we use, the more resistant the rats become. And the poison doesn’t just stop with the rats.
A threat to our wildlife
SGARs are so potent that they’re banned in the US, Canada, and the European Union. Here in Australia, however, they’re still widely used.
The problem? These poisons don’t break down quickly in the bodies of rats and mice. When a predator—like a tawny frogmouth, boobook owl, or even a powerful owl—eats a poisoned rodent, the toxin is passed up the food chain.
A study by Deakin University found that rat poison was present in 91 per cent of brushtail possums and 40 per cent of ringtail possums tested.
Powerful owls, which rely on these possums for food, are dying as a result. In effect, our efforts to control rats are killing off the very animals that help keep rodent populations in check.
A brewing public health crisis
It’s not just wildlife at risk. As more poison enters the environment, it can contaminate waterways and potentially impact human health.
As rats become harder to kill, infestations could become more common, bringing with them the risk of disease and property damage.
Alicia Gorbould warns that unless we change our approach, we could be facing a full-blown public health crisis. ‘If you’re using one of the baits that don’t work, people will probably try to use more, and more, and more,’ she says.
‘It’s feeding back into that cycle of increasing the rates of resistance in the population, increasing those non-targeted poisonings, and then we’re ending up essentially with a public health issue because we’ve got these rats that can’t be controlled.’
What can you do? Smarter, safer solutions
So, what’s the answer? Gorbould and other experts recommend ditching the poisons and focusing on prevention and physical control methods. Here are some practical steps you can take:
Seal up entry points: Rats can squeeze through tiny gaps. Check your home for holes and cracks, especially around doors, windows, and pipes, and seal them up.
Remove food sources: Don’t leave pet food out overnight, and make sure your compost bin is sealed. Store food in airtight containers.
Keep it tidy: Clear away clutter in your garden and around your home, as rats love to hide in piles of wood, leaves, or rubbish.
Use physical traps: Snap traps, electric traps, and even some natural deterrents (like corn gluten meal or salt-based products) can be effective without risking the health of native wildlife.
Encourage natural predators: If you’re lucky enough to have owls or other birds of prey in your area, do what you can to protect and encourage them—they’re nature’s own pest control.
A call for a national strategy
Experts agree that Australia needs a coordinated, strategic approach to rodent control. Until then, it’s up to all of us to do our part.
By changing our habits and avoiding the use of dangerous poisons, we can help protect our homes, our health, and our precious native wildlife.
Have you noticed more rats lately?
We want to hear from you! Have you had trouble with rats in your area? What methods have you found effective (or not)? Share your stories, tips, and questions in the comments below—let’s help each other keep our homes safe and our wildlife thriving.
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I’m not certain, so I’d have to look it up in my Funk & Wagnalls, but they look like they are related to about 60% of the politicians out there.