Australia has a serious mouse problem right now, and for farmers and rural communities caught in the middle of it, life has become pretty miserable. What started as a spike in mouse numbers has turned into a full-scale infestation, with millions of rodents working their way through crops, homes, sheds, and pretty much anything else they can get into. For many people in affected areas, mice have simply become something they deal with every single day.
The house mouse behind all of this isn’t even originally from Australia. Research suggests it arrived on European ships in the late 1700s and has been making itself at home in Australian farming regions ever since. A run of good harvests, an abundance of grain, and the right weather conditions all came together to create the kind of environment where mice breed extremely fast, according to the Grains Research and Development Corporation.
Australia has been through this before, with major outbreaks in 1984, 1993, 2011, and then the massive plague that struck eastern Australia in 2020 and intensified through 2021. The current situation is hitting grain-growing parts of Western Australia particularly hard, with some farmers reporting thousands of mice per hectare. They’re getting into everything—homes, schools, grain silos, and farm machinery—while eating newly planted seeds, contaminating grain stores, chewing through wiring, and causing serious financial damage.
Australia has natural predators that feed on mice, including owls, snakes, foxes, and eagles. The problem is they simply can’t multiply fast enough to keep up when mouse numbers explode during a plague. The standard bait used to control mice, called ZP25, has also been falling short. When there’s plenty of natural food available, mice tend to nibble at the bait rather than consume enough to kill them. In response, the Australian Pesticides and Veterinary Medicines Authority approved an emergency permit in May 2026 for a stronger version called ZP50—double the strength and capable of delivering a lethal dose from just a single grain.
The stronger bait does raise some concerns, including for people who are uncomfortable with lethal pest control methods altogether. Poisoned mice can also be eaten by birds of prey and other wildlife, creating a risk of secondary poisoning spreading up the food chain. Regulators believe careful use can keep that risk under control, but it remains something worth monitoring.
Most researchers think the plague will gradually wind down as cooler temperatures arrive, disease spreads through the mouse population, and food becomes harder to find. But for the people living through it right now, the reality is that conditions could remain extremely difficult for several more months.
