Species Introduced during Colonisation
From Stowaways to Ecological Disruptors in Victoria
Mice and rats—small, often overlooked creatures—have played a significant role in reshaping Victoria’s environments since colonisation. Unlike dingoes or native rodents, the house mouse (Mus musculus), the black rat (Rattus rattus), and the brown rat (Rattus norvegicus) were all introduced species, arriving with European ships in the late eighteenth and early nineteenth centuries (Rolls 1969). Stowaways in grain, straw, and cargo, these rodents thrived in the new colonial landscapes. They rapidly multiplied in homesteads, barns, and wheatfields, becoming destructive pests to agriculture while also undermining Indigenous food systems, spreading disease, and competing with native species.
Arrival in Victoria
Ship-borne invaders: Rats and mice were among the earliest non-native mammals to arrive in Australia. The black rat and brown rat came aboard sailing ships as early as 1788, while the house mouse spread rapidly from grain stores aboard ships and supply convoys (Rolls 1969).
Spread inland: By the 1830s, as sheep stations and wheat farms expanded in Port Phillip (Victoria), rodents moved inland along trade routes, thriving wherever grain and livestock feed were stored (Coman 1999).
Colonial reports: Early settlers frequently wrote of plagues of mice overrunning barns and homes, while rats became infamous for raiding stores, gnawing through flour bags, and contaminating food (The Argus, 1857).
Wadawurrung Country and Indigenous Perspectives
On Wadawurrung Country—covering Geelong, Ballarat, and the volcanic plains—the arrival of rats and mice symbolised another wave of ecological invasion.
Displacement of native rodents: Before colonisation, Indigenous peoples hunted and coexisted with native rodents such as the swamp rat (Rattus lutreolus) and bush rat (Rattus fuscipes). The arrival of black and brown rats displaced these species, upsetting the ecological balance (Clark 1990).
Food security disruption: House mice raided food stores and yam grounds. Indigenous families, already facing the loss of murnong (yam daisy) due to sheep and rabbits, now contend with rodents consuming what little remains.
Symbolic disruption: Rats and mice had no totemic or spiritual place in Wadawurrung cosmology. They were viewed as foreign beings—outsiders tied to the arrival of colonists, ships, and settlement.
Adaptation: Some Indigenous communities used rats as a supplementary food source in times of scarcity, a practice recorded across parts of Australia (Flood 1983). Yet unlike native rodents, introduced rats held no cultural law or spiritual standing.
Ecological Impacts
Agricultural Destruction
Mice: House mice bred explosively in grain-growing regions. Plagues were recorded from the mid-nineteenth century onwards, devastating wheat harvests and causing major economic losses (Coman 1999).
Rats: Black rats thrived in homesteads and barns, while brown rats spread through sewerage and wharf systems in Melbourne. Both species consumed grain, contaminated food, and spread disease.
Competition with Native Species
Introduced rats displaced native rodents through competition for food and direct predation on eggs, chicks, and small animals.
Their dominance disrupted local food chains, reducing prey availability for owls, snakes, and small carnivorous marsupials.
Spread of Disease
Rats were associated with typhus and plague, periodically flaring in colonial Melbourne and port towns.
House mice carried parasites that spread through agricultural and rural communities.
Colonial Society and Control Measures
Infestation in homes: Settlers complained of rats and mice overrunning houses, gnawing furniture, and consuming food. The Argus (1857) reported, “The rat is a greater enemy than the native cat [quoll], being everywhere at once.”
Control attempts: Cats were introduced in larger numbers partly to control rodents—though they themselves became destructive predators of native fauna (Rolls 1969).
Poisons and traps: From the nineteenth century onward, arsenic baits, strychnine, and later commercial poisons were used, but with limited success.
Persistence: Despite more than 150 years of control, rats and mice remain widespread and deeply entrenched across Victoria.
Case Studies: Mouse Plagues in Victoria
1917 Plague
Following a bumper wheat harvest, rural Victoria was inundated by mice.
Reports described barns, homesteads, and fields “alive with movement” as millions of mice consumed crops.
Farmers lost grain stores, while communities endured sleepless nights as mice swarmed through homes (Rolls 1969).
1993 Plague
One of the worst twentieth-century outbreaks followed record grain harvests in northern Victoria and New South Wales.
CSIRO estimated billions of mice across southeastern Australia.
Farmers lost entire silos of wheat; machinery and wiring were destroyed by gnawing; haystacks collapsed under the weight of burrows (Coman 1999).
Poisoning campaigns were implemented, but secondary poisoning affected raptors and other predators.
2021 Plague
After years of drought, heavy rains in 2020 created abundant crops and food sources, sparking a massive outbreak across Victoria and NSW (CSIRO 2021).
Rural towns reported infestations in hospitals, schools, and supermarkets.
Psychological distress was widespread: families described sleepless nights, ruined food, and the constant sound of scratching in walls.
Indigenous ranger groups noted that Country itself was “suffocating under imbalance,” linking the plague to disrupted ecological cycles and the loss of native predators.
Population Then and Now
Colonial era (1830s–1840s): Rats and mice were firmly established in settlements across Victoria.
Nineteenth century: Agricultural expansion caused rodent populations to soar, particularly during years of abundant grain harvests.
Today: Rats and mice are found across Victoria—from farms to cities to national parks—with periodic mouse plagues continuing in rural areas. The 2021 event demonstrated how persistent and damaging these outbreaks remain (CSIRO 2021).
Symbolism and Meaning
For colonists: Rats and mice represented pests and hardship, symbols of filth, disease, and agricultural loss—yet also the inevitable by-product of colonial expansion.
For Indigenous peoples: They embodied imbalance and intrusion—alien animals tied to dispossession, ecological degradation, and cultural disconnection from Country.
Today: Rats and mice persist as emblems of invasive resilience, thriving in the human-modified landscapes where many native species cannot.
Conclusion
The history of rats and mice in Victoria is one of stowaways turned ecological disruptors. From their arrival on colonial ships to their spread across farms and towns, these rodents transformed landscapes, undermined Indigenous food systems, and devastated agriculture.
For the Wadawurrung and other Victorian Indigenous nations, rats and mice symbolised the intrusion of alien beings without cultural place—competing with native kin and deepening the imbalance brought by colonisation. Mouse plagues, from 1917 to 1993 and again in 2021, reveal how disruption persists through cycles of ecological collapse, reminding us that even the smallest creatures can leave the largest marks on Country.
References
Clark, I D 1990, Aboriginal Languages and Clans: An Historical Atlas of Western and Central Victoria, 1800–1900, Monash University, Melbourne.
Coman, B J 1999, Tooth and Nail: The Story of the Rabbit in Australia (includes notes on mice and rats in colonial agriculture), Text Publishing, Melbourne.
CSIRO 2021, Mouse Plague in Australia, CSIRO Publishing, Canberra.
Flood, J 1983, Archaeology of the Dreamtime, Collins, Sydney.
Rolls, E C 1969, They All Ran Wild: The Animals and Plants that Plague Australia, Angus & Robertson, Sydney.
The Argus (Melbourne), 1857, Colonial reports on rats in homesteads and stores.
Written, Researched and Directed by James Vegter (16 September 2025)
MLA
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