Killer Kitties Wreak Critter Havoc

This is Scientific American 60-Second Science. I'm Sophie Bushwick. Got a minute?
Beneath its adorable exterior, is your cat hiding the heart of a killer?
Researchers now estimate that each year, domestic cats kill billions of birds and mammals in the United States alone.
The report is in Nature Communications.
We already knew that domestic cats can wreak havoc on islands, causing 14 percent of species extinctions and ranking as one of the world's 100 worst invasive species.
But now, scientists have reviewed previous studies to find just how much damage cats do on the mainland.
Cats kill some 1.4 to 3.7 billion birds and 6.9 to 20.7 billion small mammals in the U.S.each year.
These numbers mean that felines may be the biggest human-related cause of death for American birds and mammals.
And cats tend to prey on native species, which can cause major ecosystem damage.
The worst feline killers are those without owners, and reducing feral cat populations is an ongoing problem.
But you can still reduce the impact of domestic cats by keeping your pet indoors,
thus leaving the neighborhood a little less red in tooth and claw.
Thanks for the minute, for Scientific American 60-Second Science. I'm Sophie Bushwick.