Cuddly, but deadly.

• Position: Cats - Brief article

For all the cute videos of cats that play piano or flush toilets, here's a shocking truth: Cats aren't always pussycats. A new report by scientists at the Smithsonian and the Fish and Wildlife Service estimates that in the U.S. alone, cats kill about 2 billion birds and 12.3 billion mammals a year, from chipmunks and rabbits to rats; that's up to four times previous estimates. The report is likely to fuel a longstanding debate: Environmentalists see free-roaming cats as an invasive species that...