Your pet cat may not be as cute and cuddly as you might think. According to a new study published Tuesday in the journal Nature Communications, domestic cats kill billions of birds, mice and small animals in the U.S. each year.
Biologists estimated that cats are responsible for the deaths of as many as 3.7 billion birds and 20.7 billion smaller animals, including mice, voles and chipmunks, the Agence France-Presse reported. The study also concludes that cats are likely the No. 1 killer of birds and small mammals in the country.
Led by Scott Loss of the Smithsonian Conservation Biology Institute, the study drew from past research on the predatory habits of cats. While previous studies have suggested cats are responsible for billions of small creature deaths, the most recent estimates are significantly higher.
"The magnitude of wildlife mortality caused by cats that we report here far exceeds all prior estimates,” the report stated, according to the International Business Times.
Indeed, an August 2012 University of Georgia study, produced in conjunction with National Geographic, projected that free-range house cats kill about 4 billion wildlife animals per year, 500 million of which are birds. During the study, researchers attached video cameras to 60 cats to monitor how the felines spend their time. They found that one-third of a cat's day is spent killing smaller creatures, Mother Nature Network reports.
In the new study, researchers surmised there are about 84 million cats owned in the U.S. They estimated that each cat kills between four and 18 birds per year and eight to 21 small mammals annually, LiveScience reports.
However, it's feral cats -- an estimated 30 million to 80 million of which live in the U.S. -- that pose the greatest threat. As LiveScience notes, each of these unowned cats kills 23 to 46 birds and 129 to 338 tiny creatures per year.
Though the study was limited to U.S. cats, the murderous tendencies of felines are not. That's why Gareth Morgan, an outspoken economist and environmentalist, is pursuing a campaign against cats in New Zealand.
On his website "Cats To Go," Morgan proposes that cat owners neuter their pets and do not welcome any more felines into their households. He also calls for a mandatory, country-wide cat registration and has even suggested that New Zealanders set up cat traps to catch stray animals so they can be euthanized.
While Loss and his team are not recommending such a drastic scheme to cut down on U.S. wildlife deaths, the study does call for "conservation and policy intervention" in order to reduce environmental impact.