Before the 1917 mouse plague was brought under control, the people of Australia caught and killed over 1,500 tons of mice, equivalent to approximately 100 million individuals.
Brown rats and house mice pose a significant problem in Australia, especially around grain-growing areas in the east and south. Every few years, mouse populations reach enormous sizes, devastating crops and gardens, and invading homes, hotels, and restaurants. Even urban areas like Sydney are estimated to host a staggering number of mice, ranging from 500 million to one billion. The ratio of mice to residents is at least 100 mice per person, according to Amusing Planet.
Men standing behind a pile of 500,000 dead mice caught in May 1917 in Lascelles, Victoria. (Photo: F.G. England).
One of the largest mouse plagues occurred in 1917 when many areas in Queensland and Victoria were overrun by mice. They bit infants in their cribs, chewed on telephone wires and telegraph machines, and gnawed on stamps and parcels at train stations. Mice would leap out every time drawers and cupboards were opened, causing panic among the household members. Housewives often found dead mice floating in milk containers and had to slice bread carefully as sometimes there were cooked mice inside. Some mice even ventured into zoos, frightening lions or causing elephants to trumpet loudly.
“Order was disrupted; mice not only ran around when cats were absent but also frolicked about, nibbling on the ears and tails of the cats. The cats became so frightened and panicked that they took refuge in trees whenever possible,” reported The Richmond River Herald and Northern Districts Advertiser. According to The Horsham Times, wheat at the Woomelang station quickly disappeared. Local farmers could not use straw for feeding horses as the straw piles were infested with too many mice. Most farmers had to burn it and purchase straw from other towns.
Dozens of mice were caught and killed per person. The largest mouse extermination occurred in Lascelles, Victoria, where 200,000 mice, weighing a total of 3 tons, were captured in one night. The mouse plague was first noted in February and March of 1917, peaking between mid-April and August. Before the plague was controlled, over 1,500 tons of mice, equivalent to approximately 100 million individuals, were killed.
The 1917 mouse plague was extensive, but the most severe economic impact was from the 1993 plague, which caused damages of $64-$96 million. Mice destroyed thousands of hectares of crops and devastated poultry farms.
Researchers still do not fully understand why Australia periodically experiences mouse plagues. This invasive species is not native to the continent. They appeared alongside European settlers, possibly in the late 18th century. As a non-native species with no natural predators, mice proliferated and their numbers skyrocketed. The most significant factor contributing to mouse plagues is likely weather. Winter rains are essential for plagues to occur, though they are not the only factor. Conversely, drought conditions can prevent mouse plagues. Available food is another contributing factor, but controlled experiments have shown no change in numbers when additional water or food was provided.
