Feral cats are one of Australia's most successful and destructive invasive animals. Although the same species as our domestic pet cats (Felis catus), feral cats live and reproduce in the wild with little to no contact with people.
The threat posed by Cats has been recognised by the Tasmanian Government with cats being prohibited in a number of areas in Tasmania including National Parks, Conservation Areas, State Forest, private property with a conservation covenant under the
Nature Conservation Act 2002 and areas declared prohibited under the
Cat Management Act 2009. Cats found in these areas may be trapped, seized or humanely destroyed by responsible people identified in the Cat Management Act 2009 to undertake these cat management actions. Similarly, primary producers, and people working on their behalf, are able to trap, seize or humanely destroy any cat found on production land and production premises. On other private land that is more than 1km from a place of residence, the property owner can trap, seize or humanely destroy a cat. Cats found on private land may be humanely captured and returned to their owners or taken to a Cat Management Facility.
Behavioural attributes
Feral cats tend to avoid people but may use human built infrastructure for shelter and agricultural livestock for food. Feral cats:
- Will either run or freeze still if approached by people and will show signs of anxiety and stress in the presssence of a person. in threatening situations, feral cats can display agressive behaviour that can cause injury or harm to both human or cat.
- Tend to have more nocturnal behaviour than domestic pet cats, however feral cats will also hunt and move in daylight hours.
History
Cats probably first arrived in Australia as pets of European settlers during the 18th century. By the 1850s, feral cat populations had been reported in the wild in Australia. It is known that intentional releases of cats were made in the late 1800s, particularly around farms and homesteads, in the hope that they would control rabbits, rats and mice.
Distribution
Feral cats have been recorded in most habitats in Australia, including many offshore islands. Recent estimates suggest that there are between 2.1 to 6.3 million feral cats inhabiting 99% of the Australian land mass. In Tasmania feral cats are known to inhabit all areas of mainland Tasmania including remote parts of the southwest wilderness area and several offshore islands. Populations densities across Tasmania vary significantly depending on food and shelter availability. Recent studies in Tasmania have shown that feral cats can live in extremely high densities in and around sea bird rookeries with estimates of approximately 45-55 cats/km2 which is very high compared the national average of between 0.2 and 0.7 cats/km2.
Environmental impacts
Feral cats have a negative impact on native wildlife, livestock and human health through predation, competition, and disease transmission. Cats have been shown to prey on at least 400 species of native and introduced vertebrates in Australia, including 157 reptiles, 123 birds, 58 marsupials, 27 rodents and 21 frogs. Studies in Tasmania have shown feral cats can catch and kill wildlife weighing up to four kilograms, under surplus predation by killing multiple seabirds in a single night and reducing bandicoot numbers in urban and peri-urban landscapes.
Nationally, feral cats kill an estimated 466 million reptiles, 350 million mammals and 377 million birds annually. This all equates to approximately 2000 native species killed every second by feral cats in Australia. The impacts are not isolated to their appetite alone, with disease associated with feral cats estimated to cost 6 billion in agricultural loses and human health expenditure, with approximately 550 human deaths attributed to cat-dependent diseases annually.
The disease risk posed by feral cats is not well understood with more common diseases such as toxoplasmosis and sarcosporidiosis known to have a significant impact on the agriculture. Toxoplasmosis is known to cause debilitation, miscarriage and congenital birth defects in humans and other animals, however its potential negative impact on human mental health is also of increasing concern. Feral cats also represent a high-risk reservoir for exotic diseases such as rabies if an outbreak were to occur in Australia.
Reproduction
Feral cat ready to pounce
Image: Daryl Panther
Cats can start reproducing as young as four months of age and can reproduce for all of their adult life. Females produce up to three litters a year (65 day gestation) averaging four kittens per litter. Their high reproduction ability keeps populations growing.
Feral cat populations are self-sustaining and do not need recruitment from the domestic population to maintain their numbers. Longer breeding seasons have been noted in drier, warmer areas compared to cooler wetter places.
Control measures
The eradication of feral cats from mainland Tasmania is currently not feasible due to lack of effective broad-scale techniques, resource and logistical constraints and recruitment from domestic cat communities. Nonetheless, recent management efforts have focused on the control and eradication of feral cats from several of Tasmania’s offshore islands. Many of these islands provide high biodiversity values and once free from feral cats show significant recovery and provide a future safe haven for a range of at-risk species.
In Tasmania, the
Cat Management Act 2009 allows primary producers, and people working on their behalf, to trap, seize or humanely destroy any cat found on production land and production premises. On other private land that is more than 1 km from a place of residence, the property owner can trap, seize or humanely destroy a cat. Cats found on any private land may be returned to their owners or taken to a Cat Management Facility
Any effective, long-term suppression of feral cat numbers and impacts will likely require a change in public attitudes to cat ownership and the develop of new and effective management tools.
Did you know?
Feral cats are carnivores and can survive with limited access to water, as they use moisture from their prey.
More information
For advice on feral cat management in Tasmania, contact the Invasive Species Branch on 03 6165 3777, or visit our
Responsible Cat Ownership in Tasmania website.
The PestSmart Connect Toolkit provides information and guidance on best-practice invasive animal management on several key vertebrate pest species including rabbits, foxes, feral pigs and feral cats.
Research papers - disease impacts of feral cats
-
Australian Journal of Zoology 62(4): 272-283: "Regional seroprevalence of Toxoplasma gondii antibodies in feral and stray cats (Felis catus) from Tasmania." Fancourt, B. A. and R. B. Jackson (2014).
- Source: Legge, S. et al. (2017).
Enumerating a continental-scale threat: How many feral cats are in Australia? Biological Conservation, Vol. 206, pp.293-303
-
Woinarski, J. C. Z., et al. (2017). How many birds are killed by cats in Australia? Biological Conservation 214, 76–87.
https://doi.org/10.1016/j.biocon.2017.08.006
-
Woinarski, J. C. Z., et al. (2018). How many reptiles are killed by cats in Australia? Wildlife Research 45, 247–266.
https://doi.org/10.1071/WR17160
-
Legge, S., Woinarski, J. C. Z., Dickman, C., Murphy, B. P., Woolley, L.-A., Calver, M. (2020). We need to worry about Bella and Charlie: The impacts of pet cats on Australian wildlife. Wildlife Research.
https://doi.org/10.1071/WR19174
-
Legge, S., Taggart, P.L., Dickman, C.R., Read, J.L., Woinarski, J.C.Z. 2020. Cat-dependent diseases cost Australia AU$6 billion per year through impacts on human health and livestock production. Wildlife Research 47(8), pp. 731–746. https://doi.org/10.1071/WR20089