We know feral cats are an enormous problem for wildlife – across Australia, feral cats collectively kill more than three billion animals per year.

Cats have played a leading role in most of Australia’s 34 mammal extinctions since 1788, and are a big reason populations of at least 123 other threatened native species are dropping.

But pet cats are wreaking havoc too. Our new analysis compiles the results of 66 different studies on pet cats to gauge the impact of Australia’s pet cat population on the country’s wildlife.

The results are staggering. On average, each roaming pet cat kills 186 reptiles, birds and mammals per year, most of them native to Australia. Collectively, that’s 4,440 to 8,100 animals per square kilometre per year for the area inhabited by pet cats.

If you own a cat and want to protect wildlife, you should keep it inside. In Australia, 1.1 million pet cats are contained 24 hours a day by responsible pet owners. The remaining 2.7 million pet cats – 71% of all pet cats – are able to roam and hunt.

What’s more, your pet cat could be getting out without you knowing. A radio tracking study in Adelaide found that of the 177 cats whom owners believed were inside at night, 69 cats (39%) were sneaking out for nocturnal adventures.

Surely not my cat

Just over one-quarter of Australian households (27%) have pet cats, and about half of cat-owning households have two or more cats.

Many owners believe their animals don’t hunt because they never come across evidence of killed animals.

But studies that used cat video tracking collars or scat analysis (checking what’s in the cat’s poo) have established many pet cats kill animals without bringing them home. On average, pet cats bring home only 15% of their prey.

Collectively, roaming pet cats kill 390 million animals per year in Australia.

This huge number may lead some pet owners to think the contribution of their own cat wouldn’t make much difference. However, we found even single pet cats have driven declines and complete losses of populations of some native animal species in their area.

Documented cases have included: a feather-tailed glider population in south eastern NSW; a skink population in a Perth suburb; and an olive legless lizard population in Canberra.

Urban cats

On average, an individual feral cat in the bush kills 748 reptiles, birds and mammals a year – four times the toll of a hunting pet cat. But feral cats and pet cats roam over very different areas.

Pet cats are confined to cities and towns, where you’ll find 40 to 70 roaming cats per square kilometre. In the bush there’s only one feral cat for every three to four square kilometres.

So while each pet cat kills fewer animals than a feral cat, their high urban density means the toll is still very high. Per square kilometre per year, pet cats kill 30-50 times more animals than feral cats in the bush.

Most of us want to see native wildlife around towns and cities. But such a vision is being compromised by this extraordinary level of predation, especially as the human population grows and our cities expand.

Many native animals don’t have high reproductive rates so they cannot survive this level of predation. The stakes are especially high for threatened wildlife in urban areas.

Pet cats living near areas with nature also hunt more, reducing the value of places that should be safe havens for wildlife.

The 186 animals each pet cat kills per year on average is made up of 110 native animals (40 reptiles, 38 birds and 32 mammals).

For example, the critically endangered western ringtail possum is found in suburban areas of Mandurah, Bunbury, Busselton and Albany. The possum did not move into these areas – rather, we moved into their habitat.

What can pet owners do?

Keeping your cat securely contained 24 hours a day is the only way to prevent it from killing wildlife.

It’s a myth that a good diet or feeding a cat more meat will prevent hunting: even cats that aren’t hungry will hunt.

Various devices, such as bells on collars, are commercially marketed with the promise of preventing hunting. While some of these items may reduce the rate of successful kills, they don’t prevent hunting altogether.

And they don’t prevent cats from disturbing wildlife. When cats prowl and hunt in an area, wildlife have to spend more time hiding or escaping. This reduces the time spent feeding themselves or their young, or resting.

In Mandurah, WA, the disturbance and hunting of just one pet cat and one stray cat caused the total breeding failure of a colony of more than 100 pairs of fairy terns.

Benefits of a life indoors

Keeping cats indoors protects pet cats from injury, avoids nuisance behaviour and prevents unwanted breeding.

Cats allowed outside often get into fights with other cats, even when they’re not the fighting type (they can be attacked by other cats when running away).

Roaming cats are also very prone to getting hit by a vehicle. According to the Humane Society of the United States, indoor cats live up to four times longer than those allowed to roam freely.

Indoor cats have lower rates of cat-borne diseases, some of which can infect humans. For example, in humans the cat-borne disease toxoplasmosis can cause illness, miscarriages and birth defects.

But Australia is in a very good position to make change. Compared to many other countries, the Australian public are more aware of how cats threaten native wildlife and more supportive of actions to reduce those impacts.

It won’t be easy. But since more than one million pet cats are already being contained, reducing the impacts from pet cats is clearly possible if we take responsibility for them.

Jaana Dielenberg, University Fellow, Charles Darwin University; Brett Murphy, Associate Professor / ARC Future Fellow, Charles Darwin University; Chris Dickman, Professor in Terrestrial Ecology, University of Sydney; John Woinarski, Professor (conservation biology), Charles Darwin University; Leigh-Ann Woolley, Adjunct Research Associate, Charles Darwin University; Mike Calver, Associate Professor in Biological Sciences, Murdoch University, and Sarah Legge, Professor, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australians have more pet cats than ever before – more than 5 million in total. With the growing number, expectations on pet owners are shifting.

Many cat owners are now voluntarily keeping their cats indoors or in secure runs, and local governments mandate it in some areas. But most pet cats in Australia still roam local streets and gardens.

Broader adoption of keeping cats safe at home would have large benefits for cat welfare, human health, local wildlife and even the economy. So, should pet owners be required to keep their pets contained to their property, as dogs are?

We put that question to thousands of people in a national survey in late 2023, and recently published the results.

We found most people support requiring owners to contain cats. Just one in 12 people (8%) are opposed. The time might be right for nationwide change in how we manage our pet cats.

Local councils are embracing cat containment

From November 1, Geelong City Council will join a fast-growing group of local governments in urban and regional areas that require pet cats to be securely contained 24 hours a day.

More than a third of local councils in Australia now require cats to be contained overnight or 24 hours a day. Most are in the ACT and Victoria.

Given how good cats are at climbing and jumping, containing cats usually requires keeping them indoors or in secure runs.

The main reasons cited by local govenments for these regulations are:

• improving pet welfare: contained cats live longer and healthier lives with fewer vet bills because they are protected from traumatic injuries from car accidents, dog attacks and cat fights, infections, diseases and other misadventures.

• saving wildlife: four out of five cats allowed outside will hunt and kill an average of two to three animals per week. With millions of pet cats in Australia, each year this adds up to 6,000–11,000 animals killed in our suburbs per square kilometre and 323 million native animals killed nationally. Night curfews only protect nocturnal species such as possums.

• reducing nuisance to neighbours: containment results in less disturbance from cat fights and prevents the neighbour’s cat killing the birds and lizards living in your backyard or nearby park, which many community members value.

The public health toll of roaming cats

Another major benefit is less talked about. Stopping pet cats from roaming would greatly reduce rates of cat-borne diseases.

Several diseases which could not exist without cats can be passed to humans. These cost Australia more than $6 billion a year based on costs of medical care, lost income and other related expenses.

The most widespread of these diseases is toxoplasmosis, a parasitic infection that can be passed to humans but must complete its life cycle in cats. Australian studies have reported human infection rates between 22% and 66% of the community.

Cat-borne diseases cause considerable community harm, with an estimated 8,500 hospitalisations and 550 deaths from acute infections and also from increased rates of car accidents, suicides and mental health issues in infected people.

Pet cats are crucial to the rates of these diseases in the community. In suburbs that do not require containment, you’ll find up to 100 roaming pet cats per square kilometre.

Eliminating stray cats from our suburbs is also important to reduce disease rates – just one of the reasons why people should not feed stray cats.

Most of us support containment

A policy requiring all cats to be contained has clear benefits. But would it have support? Rules only produce benefits if people follow them.

This is why colleagues at Monash University and I surveyed more than 3,400 people on whether they would support policies that “require cat owners to keep their cat contained to their property”.

We found a clear majority (66%) of people support cat containment. A strikingly small proportion of people, about one in 12 people (8%), are opposed. The remaining 26% were ambivalent, selecting “neither support nor oppose”.

Other surveys have found almost half (42% or 2.2 million) of Australia’s pet cats are already kept contained by their owners.

Some councils can’t legally require cat containment

Our findings suggest communities would broadly support their local councils if they moved to require cats to be contained.

While councils are responsible for pet issues, state and territory laws greatly influence what councils can and can’t do.

In New South Wales and Western Australia, state laws actually prevent local councils from requiring cat containment (except for in specific circumstances, such as in declared food preparation areas in NSW).

Rules are just the start

To boost compliance, councils need to invest in communicating new rules and the reasons for them. After a grace period, council officers will also need to monitor and enforce the rules.

Communities may need support too, especially if there are costs involved. Councils could, for example, offer rebates for flyscreens to stop cats slipping out of open windows.

Working with other colleagues in 2020, we surveyed Australia’s local governments about their approaches to cat management. Most reported tiny budgets for cat management.

Local governments should not be left to shoulder the cost alone. Federal, state and territory governments are also responsible for Australia’s wildlife (and human health). These governments have a range of projects covering both feral and pet cats.

The Australian government collects A$3 billion a year in GST from spending on pets. Diverting a small proportion into responsible pet ownership programs would make an enormous difference.

Containment has wide backing

Our research shows the community is ready for widespread reform of how we manage all these cats.

Requiring pet cats to be contained is a sound policy choice. But to realise the full benefits, we also need to invest in effective communication for communities, provide rebates to help contain cats, and make sure the rules are followed.

This research was a team effort, involving Kim Borg, Melissa Hatty and Emily Gregg for the national survey, and Sarah Legge, John Woinarski and Tida Nou for the research on cat impacts and management.

Jaana Dielenberg, University Fellow, Charles Darwin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.