Elegant Assassins
4/2/26 - Our love of cats vs. our love of wildlife
Hello everyone:
I’ve been thinking about birds as spring migration season gets underway, and worrying about the millions of them who will die in collisions with windows. My essay “For the Birds” lays out the problem and some solutions. Please take a look.
This week, though, I’ve finally gotten around to writing about a much larger threat to birds. Cat-lovers, be good to me. I mean well.
As always, please remember to scroll past the end of the essay to read some curated Anthropocene news.
Now on to this week’s writing:
Killer
The cat of my childhood was named Dirigo. The word is a Latin verb that graces the Maine state flag and means “I lead.” But we didn’t call him that for very long. Early in his life, our neighbor Jane stopped by to say, with both good cheer and some concern, “You should do something about Killer the cat. He’s been sitting on top of my mother’s bird feeder.”
Killer was a wonderful house cat and a lethally efficient outdoor hunter. Once, to our amazement, he arrived at the front door with a weasel in his mouth, very proud of himself. He furiously stomped around on the porch when we wouldn’t let him in with the carcass. My mother did manage to slow down his persecution of the birds with a bell on his collar. Killer’s life was a good one, moving freely indoors and out, well-fed and well-loved and full of the kind of stalking and killing that cats are born to do.
We worried about his predation, and reduced it somewhat, but never tried to limit his time outdoors. The dogs went out to roam, the cat went out to roam, my brother and I went out to roam; that’s how rural and suburban life was for us then. Maybe it still is for some of you, your pets, and your children. Generally, though, because society worries too much about people and not enough about wildlife, dogs are leashed and kids live hyper-scheduled digital indoor lives, but cats still haunt the neighborhood.
And this oversight is killing up to four billion birds per year (and up to twenty billion mammals) in the U.S. alone. I’m here to say that’s far too high a cost to pay for the weird privilege of letting our beloved house cats and their feral cousins - a vast and protected horde of introduced predators - roam freely.
I❤️Cats
Here’s the usual disclaimer of those who write on this topic: I really like cats. Forced to choose, I’d take a dog over a cat, but grew up cheerfully with both and still love both. My family shared our home with the aptly-named Killer, then the aptly-named Grey Kitty (a stray my housemates and I adopted in college, who I then pawned off on my parents because I was traveling the world), and now my mother has Leo (a.k.a. Leonidas), a sweet and quirky male orange tabby.
Leo is the first cat we’ve restricted to indoor life. As consolation, my mother bought him a catio where he can watch, with tail twitching, the birds, chipmunks, and squirrels at the feeder. And he has the basement to hunt for the occasional mouse.
He’s an indoor cat because we know a lot more now about the scale of feline predation on birds and other wildlife. We’ve decided that our love for cats does not extend to ignoring their capacity for unnecessary death and destruction. All pet cats should be well-loved and well-tended, but within constraints set by our love of wild creatures.
This is not a red-in-tooth-and-claw nature problem. This is an Anthropocene dilemma. You and I have been born into an era in which all of life is under the human thumb. No place or species on Earth is unaffected by human activity. Which means that all that is wild is dependent upon who we are, how we act, and what we love. For the world to survive more or less intact, we must manage both our own behavior and the behavior of those species we’ve brought with us in our bulldozing journey across the globe. Cats, however beloved, are no exception.
Just as we are now trying to reduce the ecological impacts of cows, pigs, chickens, and other livestock, so should we rein in the harms of the 600 million to 1 billion cats that surround us globally. That cats are companions rather than food only increases our obligation. They have no other purpose than serving us.
Cats Kill
Every cat lover knows that cats are perfect. But they may not know that this is as true biologically as emotionally. All cats have the same evolutionary design. Your cats might be quirky or moody or lazy, and their fur colors and patterns might be quite different from each other, but beneath the skin they’re pretty much identical to each other and to the largest cats on Earth.
An evolutionary biologist, in a 2023 Scientific American interview, explained why across the entire Felidae family - from house cats to lions and tigers - their bodies and skulls differ only in size. “Ecologically,” she says, “cats all do the same thing. They're hard-core predators. They're carnivores.” She continues:
Cats have nailed one thing so well that they all do it and just come up with slightly different sizes. That's why they're perfect evolutionarily. They don't need variation. They might get bigger or smaller, but they don't change anything else, because they're just right otherwise. They're not jacks-of-all-trades; they're masters of one.
And what they’ve mastered is hunting for meat. Like their sharp claws, keen vision, stealthy movements, and astonishing agility, cats’ jaws tell the tale. Unlike dogs, wolves, bears, and other carnivores with incisors to cut and molars to grind, cats have only slicing teeth. “This difference,” she explains, “is why foxes are perfectly happy going through garbage, whereas leopards will kill livestock instead.”
A 2022 Hakai article paints a fine portrait of cats as hunters:
Domestic cats are rarely part of an ecosystem, and despite thousands of years of domestication, cats still prefer their food at 38°C—the lukewarm temperature of fresh blood. They are far more similar to their ancestors, African wildcats, than dogs are to wolves. Their ear flaps, with 32 muscles to rotate, are extraordinarily quick at picking up high-pitched sounds like a mouse’s squeak. Their eyes are enormous on a petite head and adjust to available light like the aperture of a camera. Whiskers give them a three-dimensional sense, their sheathed claws ensure silence, and they can jump vertically, up to five times their own height without effort.
The truth is that cats’ predatory behavior is much more hard-wired than in dogs. The evolutionary distance between your golden retriever and its wolf ancestor is enormous. But your cat, even if goofy and clumsy, is still a little tiger. And remember that none of us know what our cats do, or how their behavior changes, when outside and out of sight.
Cat Food for Thought
I want to be clear about the single greatest threat to birds and other wildlife. It’s us, not cats. When we cut down forests, erase grasslands, fill in wetlands, scar the land with roads, fill our buildings with glass windows, warm the Earth’s climate, poison vast swathes of farmland with pesticides, and yes, fill the fragmented world with cute and fuzzy perfect predators, we are responsible for plucking uncounted billions of birds and other animals from existence.
The graphic above does not account for human altering and destruction of habitat, but it does assess the other major threats to birds for which we are responsible. And of those, cats are estimated to be by far the worst.
I don’t want this essay to be about the numbers, but it’s vital that they be the background for the difficult discussion about how to reimagine the place of domestic and feral cats in this human-altered world.
With that in mind, here’s some cat food for thought:
Up to 164 million cats in the U.S. (~75 million domestic, 30-80 million feral) kill an estimated 1 to 4 billion birds per year, and 7 to 20 billion mammals.
Cats kill an estimated one million native birds per day in Australia. The dead include 338 native species, 71 of which are threatened. 84% of the mortality was caused by feral cats, the rest by free-roaming house cats. There are no native cat species in Australia.
In Canada, estimates vary widely, but it seems likely that the country’s ~6 million cats are killing 100 to 350 million birds per year.
The first study on the problem in China, in 2021, estimated that cats killed at minimum, per year, 4 billion birds, 6.7 billion mammals, 2.9 billion reptiles, 3.3 billion invertebrates, 2.6 billion fishes, and 2.5 billion amphibians.
A 2011 study on the impact of invasive feral cats on islands around the world found that they “are responsible for at least 14% of global bird, mammal, and reptile extinctions and are the principal threat to almost 8% of critically endangered birds, mammals, and reptiles.”
The Times wrote about a 2023 study that identified more than 2,000 species preyed on around the globe by domestic and feral cats: “Almost half of the species were birds, followed by reptiles and mammals. An unexpected number of insects were found, including monarch butterflies, pink-spotted hawk moths and emperor dragonflies.” Of those 2,084 species, nearly 350 are threatened or at risk.
This Elegant Assassin
That excellent Hakai essay offered a big picture view of “this elegant assassin”:
The International Union for Conservation of Nature Invasive Species Specialist Group lists cats as one of the 100 worst invasive species in the world. Their paw prints are all over the scene. Numerous studies have implicated cats in the global extinction of at least 63 species—40 birds, 21 mammals, two reptiles—and contributed to the endangered status of another 587 species.
This is a local problem occurring almost everywhere across the globe. Ask your nearest wildlife rescue facility about the harm cats can do. As a director of the Tufts Wildlife Clinic explained,
cat attacks are one of the most frequent causes of injury to wildlife that are brought to the veterinary school. Many of these injuries affect young wildlife that are naïve about predators. In the majority of cases, the injuries are fatal.
You get the picture. The world is full of carnivorous cats, domestic and feral, who are doing a lot of damage. But if you’re still convinced that your sweet, lazy cat isn’t one of those who hunts birds and other animals when roaming, that’s a possibility, but it’s more likely that the killing happens out of sight. One study that placed “KittyCams” on outdoor domestic cats found that only 23% of their prey were brought back to the house. 28% were eaten, and 49% were left at the kill site.
A Difficult One
When I wrote “For the Birds,” my essay on bird mortality from window strikes, a subscriber commented on the mortality by cats and the difficulty of convincing some cat owners to keep their cats inside:
When I talk to people about why their outside cats need to remain inside, these people look at me like I just knifed them. They see the life of an indoor cat to be a greater crime than all the kills the cat will make during a lifetime outside. It’s a hot topic for sure, but one that needs to be addressed.
A Canadian researcher told the CBC that the solution is simple yet seemingly impossible: “We know what to do with cats: keep your cat indoors. But it’s getting people to do it,” he said. “So how do you get people to do it? I don’t know. It’s a difficult one.”
Part of what makes the campaign to keep house cats indoors difficult is because it’s not good vs. evil. It’s a battle of empathies. I keep reminding myself that much of what motivates cat owners who let their cats roam is concern for the cat rather than a disregard for birds or other animals. And no one wants to be told that their empathy is misguided, especially by people they perceive as cruel.
I grew up thinking that an outdoor cat was normal and appropriate. Of course, the unspoken wisdom said, a hunter should be allowed to hunt. But awareness of the Anthropocene means awareness of a deeper normal than what surrounds us in this brief weird moment. The conversation about cats is haunted by our ecological amnesia about what the fabric of nature should look like, and by our historical amnesia about where cats do and don’t belong.
The Well-Being of All Life
As with most of what ails us in the Anthropocene, I think the path forward requires expanding our empathy beyond our personal lives to the well-being of all life. Cat lovers are bird lovers too. Within expansive empathy there’s more room for a rational decision based on trusted information.
I recommend reading the American Bird Conservancy’s (ABC) “Keep Cats Indoors” site and a good Q&A at Cornell’s All About Birds. Both are by bird lovers who are also cat lovers. The ABC’s resources are more comprehensive, and Cornell has an excellent set of bullet points. Here’s a combined gist:
Cats are nonnative predators, and their populations (domestic and feral) are far larger than native predators. Thus they have an outsized impact on native species already pushed to the brink by other human-caused threats.
Indoor cats live healthier and longer lives. Indoor cats won’t get run over, poisoned, hunted by larger predators, or sick from toxoplasmosis, rabies, feline leukemia, feline immunodeficiency virus, feline herpes, tapeworms, and fleas. (And indoor cats won’t transmit toxoplasmosis or rabies to their owners.)
The KittyCam study, which took place in Athens, Georgia, noted that 85% of monitored outdoor cats exhibited at least one risky behavior. 45% of cats crossed roads, 20% entered dangerous crawlspaces and storm drains, and 25% interacted with unfamiliar cats, increasing their risk of disease transmission.
Outdoor cats will hunt even if well-fed. It’s their nature.
Knowing all this makes confining a cat to an indoor life easier, but I know it’s not necessarily easy. Part of me wants Leo to have the life that Killer had. I feel a slight tinge of guilt whenever I see him flicking his tail and making little squeaky growls while watching birds and squirrels from the wrong side of the glass or catio fence. He lives a wonderful life, with lots of birds to watch, yet he could be more free. But that’s true of all pets; they could all be more free. Our relationship with dogs, cats, and other kept animals is riddled by the shaky ethics that come with ownership of another species.
Further, I know that it would have been difficult to restrict Killer to an indoor life after years of being a free-roaming cat. When I ask here that everyone keep their cats in, I acknowledge that it may be much harder to do bring outdoor cats in than to keep them in from the beginning.
Helpfully, the American Bird Conservancy has a comprehensive page for cat-owners looking to transition their outdoor cat indoors, with resources for catio enclosures, harnesses/backpacks/strollers for taking your cat out and about, indoor enrichment strategies, and - for those not quite ready to keep the cat inside - a description and effectiveness assessment of various anti-predation devices to put on the cat. The goal is to enrich the life of our cats while also protecting wildlife.
Finally, however tricky the ethics of cat ownership might be, they pale in comparison to the ethical quandaries of managing the lives and impacts of feral cats. Those lives are more difficult, and their impacts are much greater. I’ll explore some of it next week, including the tension between the social urges to either protect or eliminate feral cats, and the failure of humane strategies to curb feral cat populations.
And then there are the hard questions. In a world disrupted and fragmented by human activity, how logical is it to prioritize “wildlife” over feral cats? Aren’t feral cats just doing their best to become natural predators in an ecosystem, and who are we to intervene? How do we justify culling these marvelous animals if we also acknowledge that their predatory lives on the margins of society are not their fault? Who gets to decide what’s best for the cats?
Again, the answers to all these questions need to come from empathy for the well-being of all life. But, as I’ll get into next week, that doesn’t make them any easier.
Thanks for sticking with me.
In other Anthropocene news:
If you read nothing else, read this: From More Than Just Parks, the Trump administration has just, by a bland and quiet little executive order, dismantled the U.S. Forest Service. This should be front-page news and Congress should be resisting it with any and all measures, but it’s a blip in the dumpster fire we call the news cycle. The article is an excoriating response to yet another truly terrible escalation from the administration in its war against science and good regulation of extractive industries. Read all of it. Here’s the opening graf:
Late Tuesday afternoon, with the subtlety of a wrecking ball and the morality of a foreclosure notice, the Trump administration announced the most devastating attack on the U.S. Forest Service in the agency’s 121-year history. Not a budget cut. Not a policy shift. Not a “reorganization.” An execution.
From Orion, “Putting the Art into Artemis,” a lovely essay on the Moon and the wealth of cultural appreciation for it from around the world and across time. The essay is also an impassioned defense of this new age of lunar exploration, despite its costs:
The Latin root of “explore” means to “utter a cry.” Every song, every tale, every prayer, every painting about the Moon has been a flight to our companion world. It’s also kept us grounded on the Earth. Lunar culture is a double-perspective, then. We look up there from right here, and, in doing so, can see both more clearly.
Also from Orion, “All for One,” an important long-form call to arms for the labor movement and the climate movement to join forces against their shared enemies, those corporate and political powers who would burn the world down before offering respect to ordinary citizens and a fair wage to ordinary workers. “An injury to one,” the old labor slogan goes, “is an injury to all.”
From Bill McKibben and The Crucial Years, “Night Into Day,” a hopeful update on the incredible growth in grid-scale battery technology that in a few short years may form the foundation for an entirely new and planet-friendlier energy system. Recently, he notes, 43% of the California grid was powered by batteries for a while after sunset, and that batteries remained above 20% for four hours. Remarkably, 90% of California’s grid battery system has been built in just the last five years. Looking ahead, solid state batteries that don’t use lithium or rare earth metals may dominate the nighttime grid.
From Rhett Ayers Butler and Nature Briefs, a brief origin story for Mongabay, now one of the world’s best sources for global news on nature and conservation. It began as an idea and a guy in his pajamas working on a laptop. As it developed, Butler made the vital decision to turn the young eco-journalism project into a nonprofit that emphasized local reporting from local journalists working in remote places, and then later made a point of emphasizing solutions alongside the environmental problems that few other outlets reported on. The lesson he draws from the origin story, he says,
is simple and somewhat reassuring. You do not have to solve everything at once. You just have to begin somewhere, keep learning, and allow others to carry the work further than you ever could alone.
Two from Grist on agriculture: The need to increase research on Indigenous agriculture in order to scale up its lessons for making food systems more resilient in a hotter world, and how clever research with optic fiber cables has revealed that tilling is destroying the capacity of soils to hold moisture and nutrients.
From the Times, the economic value of flying foxes (large fruit bats) to the Australian economy is helping to change minds about these animals whose seed-laden poop both annoys people and replenishes forests. They are pollinators and seed-dispersers whose colonies can hold several hundred thousand bats:
“Australian flying foxes are the quintessential Australian character — they range across the landscape of droughts and flooding rains,” said Dr. Welbergen, who was not involved in the new study. “With their extreme mobility, bats are a glue that keeps the increasingly fragmented Australian forest landscapes together.”
He added that the flying foxes preserve “the genetic integrity of Australia’s forests. This is especially important as landscapes recover from fires that are becoming more frequent.”
From Heated, how the oil and gas industry in Texas has gotten away with dumping massive amounts of toxic and radioactive drilling waste onto the landscape without any kind of responsibility or obligation, even though the waste has poisoned workers and become the land under which homes and schools have been built.
This is such an important conversation, Jason. One that should really be happening on a far larger and louder scale, but I’m grateful for you speaking to it and especially in a way so nuanced that it really becomes inarguable! Whenever I get called to somewhere in the village because someone’s cat has caught a bird, David always tags along and, while I never ask him to, I always hear him casually reeling off the devastating figures of deaths caused by roaming cats each year. It’s an extraordinary blind spot.
Wonderfully written article! Thank you for creating a rich resource that I can share with others (and for including my comment from your “For the Birds” essay!). So many people are entirely unaware of the staggering number of deaths caused by cats. Getting the numbers out there is so important. Having that data inside this brilliantly written essay will only help the cause.
Also, this is a powerful sentiment: “We’ve decided that our love for cats does not extend to ignoring their capacity for unnecessary death and destruction.” This hits the core of responsible cat ownership, especially since, as you point out, they are companion animals that we choose to introduce into our lives.
As for your future essay on the feral cats, that is where I find myself fully overwhelmed and conflicted. The scale is massive, the “solutions” are complex and uncomfortable but again, the discussion is necessary. I look forward to reading that essay though I’m glad I’m not the one writing it!