Sure, they can be fuzzy and cute, but let's face it, cats are big-time killers—and a new study released last week by the journal Nature Communications proves it. Domestic cats kill between 1.4 billion and 3.7 billion birds and between 6.9 billion and 20.7 billion mammals (mostly mice, shrews, rabbits, squirrels, and voles) each year, the study concludes. That's one helluva lot of critters.
Stray and feral cats, unsurprisingly, are the worst offenders, but pet cats are not exactly innocent bystanders. Researchers speculate that a single kitty may slaughter between 100 and 200 mammals annually. The authors also conclude that more animals die from cat attacks in the U.S. than in road accidents, collisions with buildings, and poisonings—combined. Scientists believe the astonishing number of bird deaths represent as much as 15 percent of the U.S.'s total bird population. (The timing of the study is remarkable: Just last week a prominent New Zealand economist caused a stir in the international feline community by calling for the eradication of cats, citing their threat to the country's unique wildlife.)
Don Jordan, director of the Seattle Animal Shelter, says he's not particularly surprised to learn of the extent of annual cat carnage: "Here in Seattle, where we have 250,000 domestic cats—and that doesn't count the number of feral or stray cats—we are seeing a profound impact on smaller rodents, salamanders, and snakes," Jordan says. "I know the Audubon Society is particularly concerned about the songbird population in Seattle" and cats' impact on their mortality, he adds.
The scientists who helped author the report urge loving cat owners to keep cats indoors when possible, and say research has shown that a properly fitted collar and bell will reduce a cat's hunting success by at least a third.