# Cats in Australia

Cats are an invasive species in Australia. They are not native to Australia and were only introduced by European colonists as pets in the early 1800s, and native Australian animals did not co-evolve with them. In 2016 the domestic cat population was 3.8 million. The feral cats population is estimated between 2.1 and 6.3 million depending on fluctuations in rainfall.
The Invasive Species Council has estimated that each year domestic and feral cats in Australia kill 1,067 million mammals, 399 million birds, 609 million reptiles, 93 million frogs, and 1.8 billion invertebrates. As one of the most ecologically damaging and the most costly invasive species in Australia, predation by both domestic and feral cats has played a role in the extinction of many of Australia's indigenous animals. For instance, cats are found to have significantly contributed to the extinction of at least 22 endemic Australian mammals since the arrival of Europeans.
For biosecurity reasons, any cats that are imported into Australia must meet conditions set by the Department of Agriculture, Fisheries and Forestry.

## Historical context

Historical records date the introduction of cats by the first settlers in 1788 and that cats first became feral around Sydney by 1820. In the early 1900s concern was expressed at the pervasiveness of the cat problem.

## Domesticated cats

Domesticated cats that are allowed to roam, kill an estimated 110 native animals each year; totaling up to about 80 million native birds, 67 million native mammals and 83 million native reptiles being killed by them annually.
Almost 30% of Australian households keep at least one domesticated cat. Domesticated cats must be microchipped in every state of Australia except Tasmania. All pet cats past six months of age must be desexed in the Australian Capital Territory, Tasmania, South Australia and Western Australia.

## Feral cats
### Ecological damage

Feral cats are a major invasive species and have been linked to the decline and extinction of various native animals in Australia. They have been shown to cause a significant impact on ground-nesting birds and small native mammals. A study in the 2010s estimated that each feral cat kills 740 wild animals per year. Feral cats have also hampered attempts to reintroduce threatened species back into areas where they have become extinct, as the cats quickly kill the newly released animals. Environmentalists conclude that feral cats have been an ecological disaster in Australia, inhabiting almost all of its ecosystems, and being implicated in the extinction of several marsupial and placental mammal species.
A field experiment conducted in Heirisson Prong (Western Australia) compared small mammal populations in areas cleared of both foxes and cats, of foxes only, and a control plot. Researchers found the first solid evidence that predation by feral cats can cause a decline in native mammals. It also indicates that cat predation is especially severe when fox numbers have been reduced. Cats may play a role in Australia's altered ecosystems; with foxes they may be controlling introduced rabbits, particularly in arid areas, which themselves cause ecological damage. Cats are believed to have been a factor in the extinction of the only mainland bird species to be lost since European settlement, the paradise parrot.

#### Predators and competition

It is sometimes falsely believed that cats in Australia have no natural predators and as such are apex predators. While this is true in some areas, cats are both preyed upon and outcompeted by both native and introduced animals. Studies of the diet of Tasmanian devils found scats of 14% of them contained cat DNA. It is strongly suspected that they specifically hunt kittens. Combined with competing for prey they have successfully suppress feral cat populations in Tasmania in areas free of devil facial tumour disease. Due to this proposals to reintroduce devils to the mainland often cite reduction of feral cat numbers as a key benefit. Likewise stomach and scat evidence shows that dingoes (and feral dogs) prey upon them and in areas where they are common, there is evidence that feral cat populations are supressed, though some dispute this. In some remote areas wedge-tailed eagles and saltwater crocodiles are known also to prey on them though this is not common.

### Claimed benefits

Some researchers argue that feral cats may suppress and control the number of rats and rabbits, and cat eradication may damage native species indirectly.

### Economic impacts

Cats are the costliest invasive species in Australia. The cost of invasive cats to the national economy is estimated to be nearly A$19 billion over the 60 years up to 2021, with most of the cost spent on population control. This cost significantly outstrips the next most costly invasive species, with rabbits in Australia coming in at nearly A$2 billion.

### Control

Pintupi, Nyirripi and other Western Desert peoples in Western Australia and Northern Territory have been hunting cats to use as a food source and for bush medicine for decades, but in 2015 they were also participating in a program with ecologists to help monitor and reduce cat predation on threatened species.
Some varmint hunters of feral cats in Australia, such as Barry Green, face backlash and even death threats for the culling of the invasive species.
Since 2016, a program on Kangaroo Island aims to fully eradicate the island's feral cat population, estimated at between 3000 and 5000, by 2030. The 2019–2020 bushfires have complicated the eradication efforts, as the gradual regrowth of the burnt brush creates favourable conditions for cat breeding and makes them more difficult to hunt. By the end of 2021, at least 850 cats had been removed from the burnt area at the western end of the island using grooming traps with state-of-the-art technology and cameras. In addition, an exclusion fence had been built on private property around some of the burnt land, helping to protect the populations of Kangaroo Island dunnart and southern brown bandicoot.

## Phantom cats

The numerous sightings of phantom cats in Australia include the Gippsland phantom cat and the Blue Mountains panther.
Australian folklore holds that some feral cats have grown so large as to cause inexperienced observers to claim sightings of cougars in Western Australia. While this rarely occurs in reality, large specimens are occasionally found: in 2005, a feline was measured to be 176 cm (69 in) from the tip of its nose to the tip of its tail in the Gippsland area of Victoria. Subsequent DNA tests showed it to be a feral cat.