Fluffy may not be such a sweetheart after all.
If you let her outside, your house cat spends about a third of her time killing smaller animals like mice, voles, chipmunks and birds, according to a study published in the journal Nature Communications.
Her feral cousin is even more blood thirsty, killing an average of 23 to 46 birds and 129 to 338 small creatures a year.
In all, biologists estimate cats kill as many as 3.7 billion birds and 20.7 billion small mammals each year in the continental United States.
The U.S. Fish and Wildlife Service funded a three-year study by the Smithsonian's Conservation Biology Institute to estimate the number of birds killed by predators, chemicals and by striking windows and wind generators.
They're interested because about a third of the 800-some species of birds in the United States are endangered, threatened or in significant decline, according to the American Bird Conservancy.
It turns out tabby is the biggest culprit.
Everyone knew cats were natural predators, but researchers were shocked by the carnage recorded by cameras attached to 60 cats turned loose during a 2012 University of Georgia study.
The issue is controversial, of course. There are 84 million pet cats in the United States in addition to 30 million to 80 million feral cats, and not everyone is a cat lover.
An outspoken economist and environmentalist in New Zealand, Gareth Morgan, is mounting a campaign for a mandatory, country-wide cat registration program plus trapping and euthanasia for wild cats.
It's definitely a tragedy that so many cats are left to fend for themselves in the wild -- even in the storm sewers of McCook, Nebraska -- and that so many songbirds are killed unnecessarily.
It's also tragic that cats are the number one animal that animal shelters are forced to euthanize each year.
Cats are only doing what comes naturally, and have served man over the centuries by killing rodents that spoil the stored grain supplies we depend upon for food.
They can be a great, no-fuss companion animal, but it's important that owners see to it that they don't contribute to the problems the new study points out.
Make sure your cat is spayed or neutered and stays home where it belongs.