In 1859, Australia released 13 rabbits for hunting. Decades later, they created one of the world’s worst invasive species crises

When European rabbits arrived in Australia in the 19th century, they were brought over as familiar game animals rather than as a threat to the environment. But within decades, their population exploded across the continent.

With few natural predators and the ability to adapt to a wide range of landscapes, rabbits spread from farmland to forests, pastures and dry interiors. Their increasing numbers began to put pressure on native plants, farmlands and fragile ecosystems, causing widespread soil erosion, destroying plants and competing with native herbivores for increasingly limited food resources. What started as a small release of imported animals has become one of Australia’s most challenging invasive species problems.

How 13 rabbits released for hunting became Australia’s biggest invasive species problem

As National Geographic reported, the story begins in 1859 when Thomas Austin, a wealthy landowner in Victoria, imported European hares for hunting. He released 13 rabbits on his property, expecting them to provide a source of sport for himself and his guests.The rabbit population has multiplied far beyond expectations. Australia’s climate and open landscape provided favorable conditions, while the absence of many of the predators found in Europe meant their numbers grew rapidly.

Within about five decades, rabbits had spread across much of the continent.By the early 1900s, large rabbit colonies had become common in many areas. Their burrows covered farmland, and their constant grazing reduced the amount of vegetation available to local animals and livestock.

Why are rabbits so difficult to control?

The European rabbit is one of the most diverse mammal species. This animal can live in different environments from grasslands to semi-arid areas, provided that sufficient resources and soil are available to build burrows.The reproductive capacity of the rabbit has made managing this problem more complex. Females of this species have the ability to reproduce all year round, and give birth to several litters every year. Moreover, each litter consists of several individuals, which provides rapid recovery even after killing a large number of animals.As a result of these factors, a large number of these mammals appeared in Australia.

It is estimated that there are up to hundreds of millions of wild rabbits in Australia.

From farmland to forests: damage has spread across Australia

The rabbit invasion has permanently changed the Australian environment. Their consumption of grasses, seedlings and native plants has led to competition between them and local wildlife for food, thus preventing the recovery of vegetation.There were huge losses for farmers. Overgrazing exposes the soil to wind and water erosion.

In some places, rabbit infestations have damaged newly planted plants and prevented native plants from reestablishing themselves.Its effects were not limited to plants alone. The decline in food sources for rabbit populations has also affected native species that depend on these food sources. On this basis, feral rabbits are classified as environmental pests in Australian conservation legislation.

Australia’s first attempts to stop the rabbit invasion

Australia has tried many methods to control rabbit populations. Early efforts focused on physical barriers, including large fences designed to prevent rabbits from moving into agricultural areas.One of the most ambitious projects was the construction of a state barrier fence in Western Australia, which stretched across hundreds of kilometres. Despite the efforts made, fences alone were not able to solve the problem because rabbits were already widespread in many areas.Farmers also began destroying rabbit pens, the underground tunnel systems in which rabbits shelter and breed. Removing these safe breeding spaces remains one of the most practical methods in areas where land managers can access and treat colonies effectively.

Virus experiences that have changed Rabbit control strategy in Australia

In the mid-twentieth century, scientists turned to biological control. In the 1950s, Australia introduced myxomavirus to control rabbit populations.

The virus infects rabbits but is harmless to most other animals.The virus caused a significant decline in rabbit populations when it first appeared. However, over time, the surviving rabbits developed greater resistance, and the disease became less effective as a means of control.The second major attempt came with Rabbit Hemorrhagic Disease Virus (RHDV). The disease attacks European rabbits and can quickly kill infected animals.

After establishing itself in the wild in the 1990s, RHDV caused a significant decline in rabbit populations, especially in dry parts of Australia.The virus has also faced restrictions. Some rabbit populations have developed resistance, while environmental conditions have affected how effectively the disease spreads. Cooler, wetter areas often saw less impact because the insects involved in transmitting the virus were less active.

From poison to prevention: evolving rabbit control efforts in Australia

Besides biological technology, poison has also been used to reduce the rabbit population. Chemicals such as sodium fluoroacetate have been used in some cases due to the high effectiveness of this technique in controlling rabbit populations.There are other methods where the burrows are fumigated using a gas that kills the rabbits living inside the burrows. These types of control measures have been used mostly in specific areas but not throughout the country.Scientists are still continuing to explore other ways to control rabbit populations. This is due to the rapid reproductive rate of rabbits and the ability of rabbits to adapt to control measures.

A problem that persists decades later

More than 160 years after the first rabbits were released, Australia is still dealing with the consequences of this introduction. The animals that once arrived as hunting companions have become one of the country’s most persistent invasive species.Completely controlling it has proven impossible, but ongoing research and management has helped reduce its impact in some areas. The challenge now is to maintain a balance between protecting Australia’s unique ecosystems and managing species that have become established throughout the landscape. Thirteen rabbits released for sport in 1859 have grown into the hundreds of millions within decades, defeated a continent-spanning fence, evolved resistance to two separate biological control viruses, and are still around 165 years later.

The story is less about a single failure of control than about what happens when a species finds a natural environment that has no evolutionary memory of it, and enough space and resources to continue reproducing faster than any intervention could reduce the population.