Image: Basile Morin (Wikipedia)

Feral cats are an ecological scourge, wreaking havoc on wild mammal, bird, and reptile populations. That doesn’t make the impact of these rogue floof monsters on Australia’s reptile population any less astonishing, though.

Every year, feral felines kill some 466 million reptiles in Australia’s natural ecosystems, according to a new paper in Wildlife Research. When pet cats and feral cats in human-modified landscapes are included, the death toll jumps to an estimated 649 million reptiles a year, or 1.8 million dead herps a day.

“Some cats eat staggering numbers of reptiles,” lead study author John Woinarski of Charles Darwin University said in a statement. “We found many examples of single cats bingeing on lizards, with a record of 40 individual lizards in a single cat stomach.”

The researchers, who’ve previously looked at how our feline overlords impact Australian birds (hint: very badly), tallied the reptilian carnage by collating results from over 80 studies that looked at lizard remains in cat stomachs and scat. Combining this with model estimates of feral cat density across Australia, they found the whiskered death machines nosh about 61 reptiles per square kilometer per year, or 225 reptiles per cat.

The slaughter seems to be highest in Australia’s hot, dry interior, which is unfortunate because that’s also where reptilian diversity tends to be greatest. In total, 258 species—about a quarter of all described Australian reptiles—are preyed upon by the non-native predators.

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Wildlife biologist Imogene Cancellare, who studies snow leopards at the University of Delaware, said she wasn’t surprised by the study’s findings.

“Ecologically and behaviorally, this is totally doable for a free-ranging cat,” Cancellare told Earther via email, referring to 225 reptilian snacks per cat per year. She noted that a previous study found feral cats are responsible for the deaths of 228-871 million reptiles in the U.S. each year, along with billions of birds and mammals.

Cancellare said the finding that feral cats are especially effective killers in Australia’s harsh interior was noteworthy. “This means that in hot climates, feral cats are taking even more reptiles in order to survive,” she said. “As climate change continues to threaten biodiversity worldwide, the impact of feral cats will be felt even more severely than it is today.”

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It’s hard to say how feral cats are impacting specific reptiles in Australia, because most population sizes are unknown. Nevertheless, the findings add urgency to Australia’s wide-ranging efforts to rein in the beasts.

Most recently, the land Down Under completed construction of the world’s largest cat-proof fence. Whether it proves more effective than baiting cats with KFC is TBD. As for what you can do to keep your own furry demon spawn from contributing to the mess, it’s pretty straightforward.

“The takeaway for this is to spay and neuter your cats, and to keep them indoors,” Cancellare said.