They look lovely and some humans adore them but cats are one of the biggest threats to endangered species in Australia, according to newly published research.
The animals may purr gently in the warmest corner of the house but when they go wild, they are utterly destructive, according to scientists.
Every year, cats kill about 1.5 million animals in urban Canberra according to the researchers.
Many of the killer cats are pets which have gone out of control.
Across Australia, the research shows that feral cats (those born wild and pets on the loose) kill more than a billion animals a year - six million a day.
In the ACT, the scientists reckon there are more than 3,000 feral cats. They estimate that across the ACT every year each one of these cats kills on average:
- 223 non-native mammals (like rabbits);
- 155 Reptiles
- 65 Birds
- 26 native mammals
- 3 frogs
The research by professors John Woinarski, Sarah Legge and Chris Dickman is published under the title "Cats in Australia: Companion and Killer".
Professor Woinarski said cat owners needed to be "responsible" and keep their animals either indoors or penned.
"We want to alert and inform all Australians to the threat cats pose to our wildlife. Our community and leaders need to manage this threat far more effectively if we want to conserve Australia's unique wildlife," he said.
Australia's mammal extinction rate is by far the highest in the world and cats have been a leading cause.Professor Sarah Legge
He added that it was false to think that cats kept down populations of rodents.
"Some may think that cats work to keep down the numbers of introduced rabbits, rats and mice, but actually these introduced species are a food source, boosting the number of cats and hence increasing their impact."
Another of the co-authors, Professor Sarah Legge, said cats were causing a "catastrophic problem".
"Australia's mammal extinction rate is by far the highest in the world and cats have been a leading cause of at least 20, or two-thirds, of our mammal extinctions over the last 200 years."
She said uncontrolled pet cats killed about 75 animals a year "but many of these kills are never witnessed by their owners."
Cats were introduced by colonists in the 19th century to control mice and rats. Some may have come on ships. Like the dog, they disrupted existing patterns of ecology - they were a new species which destroyed existing species in an uncontrolled and unpredicted way.
On top of that, pet cats go wild. Some have been known to survive in drains in the ACT.
Another of the researchers, Professor Chris Dickman, said that across Australia each day cats were killing more than 3.1 million mammals, 1.8 million reptiles and 1.3 million birds.
"Many of Australia's native species cannot withstand these high levels of predation, and will become increasingly at risk of extinction unless the problem of cats in Australia is solved."