Is your cat a mass murderer?

Little Tiddles is fluffy, adorable…and murderous.

A shocking report from the Smithsonian Conservation Biology Institute found that cats kill far more animals than was previously believed – a potentially genocidal four billion birds and 20 billion mammals a year in the US alone.

We spoke to lead researcher Dr. Scott Lost.

Metro: Which cats are the biggest killers and why?

Lost: We estimate that un-owned cats including barn cats, stray cats, cats in subsidized colonies, and cats that are completely feral are responsible for 69% of bird mortality and 89% of mammal mortality. The predation rates by this group average three times greater than rates for owned cats.

How many kills might a pet cat make in a year?

The best available data suggests that owned cats kill between 4 and 18 birds and 11 and 30 mammals per year. This is before accounting for prey items that cat owners and researchers are unable to detect, so the numbers are probably higher. Un-owned cats – because they spend 100% of their time outdoors – kill far more animals: 23-46 birds and 140-330 mammals per year, on average.

But we know cats are predators – why should we worry?

In the United States there are no native predators that are comparable to domestic cats; thus, cats represent a novel predator and threat to wildlife. The data suggests that native bird and mammal species – as opposed to ‘pests’ – make up the majority of the species preyed upon by cats. More research is needed to determine which species are most vulnerable to cats, but these should be a wildlife management priority.

What steps could/should be taken to reduce the killing?

We hope that the large amount of wildlife mortality indicated by our research alerts policy makers, wildlife managers, and scientists to the large magnitude of this problem.