Many naturalists consider domestic cats to be the most effective killers on earth, with thousands of species they can prey on.
The results of a new study published in April 2020 have researchers begging cat owners to keep their pets inside.
Australian scientists found that domestic cats are killing an estimated 230 million native birds, reptiles and mammals in Australia every year.
As well as killing native animals, pet cats were also preying on about 150 million introduced animals – mostly rodents.
“If we want native wildlife in our towns and cities – rather than introduced rodents and birds – then there are choices to be made,” says Dr. Sarah Legge, lead author of the study published in the journal Wildlife Research.
“All we need to do is keep pet cats contained.”
The researchers assembled information across 66 studies of predation by pet cats worldwide (including 24 Australian studies) to estimate the predation toll of pet cats in Australia, plus the predation pressure per unit area in residential areas.
They also compared these estimates to those published for feral cats in Australia.
The study found that each feral cat kills an average 576 native birds, mammals and reptiles per year, while pet cats kill an average of 110 native animals every year – 40 reptiles, 38 birds and 32 mammals.
The per capita kill rate of pet cats is 25% that of feral cats. In total, this meant pet cats were still killing 66.9 million native mammals, 79.7 million native birds and 82.9 million native reptiles every year.
While feral cats remain a major threat to wildlife, Dr. Legge says it’s easier for us to manage the impacts of pet cats than feral cats.
“Either keep them inside, or in secure pet runs outside,” she said.
A 2015 study by Cornell University estimated that cats kill up to 4 billion birds and 22 billion small mammals nationwide.
“They have an instinct to kill things, even if they don’t plan on eating it. A cat can kill a half dozen animals a day, and their range is enormous,” said Paul Anderson, president of the Cayuga bird club.
Dr. Sarah Zito, senior scientific officer for companion animals at RSPCA Australia, added: “Contrary to what some might believe, cats do not need to roam to be happy. Indoor cats can live longer lives, protected from all these dangers. And, if provided with everything they need, they can be just as happy at home.”