A Stone Cold Killer Lurking in Your Backyard

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   It's a cat owner's worst nightmare. Mittens slips out the catflap in the morning, only to return a few hours later with a 'present' to drop on the kitchen floor. Perhaps it's a bird, maybe it's a bunny, or heaven forbid, a rat. It's a gross habit, but it is also a terrible one. Cats’ killer instincts are a scourge on wildlife, and now a new study finds that these felines eat creatures belonging to over 2,000 species worldwide.

In fact, outdoor domesticated cats may eat more animals of different species than any other creature on Earth. What’s more, over 300 of the species they like to snack on are endangered, researchers report in the journal Nature Communications. Ultimately, the study shows house cats are a conservation threat when allowed to roam free.

Cats have to eat meat to survive — and contrary to what you think Fluffy’s picky eating habits may be, cats are decidedly not fussy. Scientists have studied the dietary habits of cats around the globe for over a century, finding that they will happily catch, kill, and devour birds, mammals, reptiles, and amphibians of all sorts.

But no one had put all these studies together to understand how free-ranging cats eat on a global scale. It’s an important measure to know, as cats contribute to about a quarter of bird, mammal, and reptile extinctions worldwide.

So, the researchers analyzed more than 500 studies, most of which included actual observations of cats eating different critters. All told, cats were observed eating 2,084 different species on all continents except for Antarctica. Some dined on creatures as big as a cow (the cat did not kill the cow but ate its remains) and as small as a ruby-throated hummingbird. Aside from the cow and some other animals, cats likely hunted and killed the bulk of their food, the researchers say.

Birds are the favorite food: Avians made up nearly half the species eaten by cats, followed by reptiles (22%), mammals (20%), insects (5%), and amphibians (2%). House mice were the most commonly observed prey item, but rats, sparrows, and rabbits weren’t far behind.

About 16% of cat-consumed species are in dire straits, either near threatened or threatened with extinction in the wild. The researchers found records of cats eating 11 species that are now extinct. Many of them lived on islands, where native animals tend to be more vulnerable to invasive predators — particularly those with an appetite, four paws with sharp claws, quick reactions, incredible agility, and a mouth full of needle-sharp teeth.

“Our findings demonstrate that cats are indiscriminate predators and eat essentially any type of animal that they can capture at some life stage or can scavenge,” the authors write. “This dietary breadth lends further evidence to the myriad ways that cats can (or may) interact with native species and disrupt ecosystems.