Study: Cats kill billions of animals a year
Cats kill billions of birds every year and even more tiny rodents and other mammals in the United States, a new study finds.
According to the research, published Tuesday in the journal Nature Communications, cats kill between 1.4 billion and 3.7 billion birds and between 6.9 billion and 20.7 billion small mammals, such as meadow voles and chipmunks.
Though it's hard to know exactly how many birds live in the United States, the staggering number of bird deaths may account for as much as 15 percent of the total bird population, said study co-author Pete Marra, an animal ecologist with the Smithsonian Conservation Biology Institute.
Staggering toll
Marra and his colleagues are looking at human-related causes for bird and wildlife deaths in the country, from windmills and glass windows to pesticides.
But first, Marra and his team looked at the impact of the feline population, one of the biggest putative causes of bird demise in the country.
While past studies had used critter cams or owner reports to estimate the number of birds killed by cats, those studies were usually small and not applicable to the entire country, Marra told LiveScience.
For this broader analysis, the team first looked at all prior studies on bird deaths and estimated that around 84 million owned-cats live in the country, many of which are allowed outdoors. "A lot of these cats may go outside and go to 10 different houses, but they go back to their house and cuddle up on Mr. Smith's lap at night," Marra said.
Based on an analysis of past studies, the researchers estimated that each of those felines killed between four and 18 birds a year, and between eight and 21 small mammals per year.
But the major scourges for wildlife were not those free-ranging, owned-cats, but instead feral and un-owned cats that survive on the streets. Each of those kitties -- and the team estimates between 30 million and 80 million of them live in the United States -- kills between 23 and 46 birds a year, and between 129 and 338 small mammals, Marra said.
And, it seems, the small rodents taken by felines aren't Norway rats or apartment vermin, but native rodent species such as meadow voles and chipmunks, he added.
No easy answers
One obvious step to reduce the mass wildlife death is to keep kitties indoors, Marra said.
Perhaps seeing their furry friends bring in a meadow vole or a cardinal will spur cat owners to say, "Listen, Tabby, we're going to have a heart-to-heart talk about how much time you spend outside," he said.
Wild cats pose tougher questions, because capture and sterilization approaches have varying levels of success depending on the community, said Bruce Kornreich, a veterinarian at Cornell University's Feline Health Center, who was not involved in the study.
While keeping owned-cats indoors is the best way to benefit both kitties and wildlife, a complete cat ban, like the one recently proposed in New Zealand, is probably not the answer, he said.
For one, it's not clear how completely removing cats from outdoors would affect the ecosystem.
"It may be in some cases that cats may also be keeping other species that may negatively impact bird and other small mammal populations in check," Kornreich told LiveScience.
Popular in SciTech
- Oops! The five greatest scientific blunders
- Apple's next iPhone may be coming in June
- Zynga demands employees return stock or get fired
- Thousands online proclaim: Jahar Tsarnaev is innocent
- 40 years later: Why the Endangered Species Act still matters
- Beam this up: Creating the sounds of "Star Trek"
- Alternatives to Google Reader
- Google security: you (still) are the weakest link














It is also dangerous to allow your cat to roam. Foxes and coyotes grab them, cars hit them and they fight (preferably, it seems, at 3 a.m.).
I keep my cats in for these reasons. To do otherwise is selfish and foolish.
So those yelling all cats should be banned, well, if you're a dog lover, then sorry, but your dog needs to go as well.
So let's just ban all pets shall we?
Now just how idiotic would that be?
I don't care what anyone says, it's NOT so much pets or animals doing the destruction or the extermination/extinction of any other animals.
It is humans, especially developers that continue to destroy and get permits to ear down natural habitats for these animals, then since there homes have been destroyed, start integratting with humans by building nests or slithering into your home, then we go and buy traps, bait or guns to rid ourselves of a pest, which in all rights lived there BEFORE the development was ever thought about, but now taken over these animals residential areas.
So leave folks pets and cats alone, unless you're willing to give up every pet or any other animal you might own.
After all, what about snakes that many owners have released into the wild?
For example because they found out later after acquiring said snake or animal it wasn't for them, cost more than they expected to take care of, or just tired of it and released it?
These animals I'm sure have caused just as much, if not more deaths of other creatures as any cat.
There is a reason and a place for everything, but the wanton destruction of animal habitats and human development has been the demise of many an innocednt animal, so we should be looking at ourselves just as hard, if not harder than any pet we own or animal on the prowl.
I must tell you, too, that I once had a dog (that I kept in my yard) that killed cats. He got three in his lifetime that had roamed into my yard. All I could think was how irresponsible those cats' owners were.
If you are going to have a pet, be responsible about having it.
How utterly desperate for you to bring snakes into this "argument!" ha!