I have had two serial killers in my life. The first was a former student. A couple of years after he graduated from my university, he murdered his father, his mother, his younger brother, and the family dog. After he was arrested, the local television station sent a reporter to interview me because I had been his academic advisor. When the reporter asked me what he was like, I stupidly looked at the camera and mumbled the classic cliché:
"Well, he was quiet and kind of shy, but he seemed like a nice guy."
The same could be said of the other killer in my life, my cat Tilley. She spends part of her days outdoors, and like most cats, she is a recreational hunter. I am usually successful in suppressing the guilt that comes with having a serial killer for a companion animal, but a recent report in the journal Nature Communications has caused me to rethink the ethics of keeping predators as pets.
Based on existing data, the researchers concluded that the havoc wreaked by cats on native animal populations has been vastly underestimated. They calculated that in the United States, cats kill somewhere between 8 and 24 billion small, feathered, and furry creatures a year, and are the largest human-related source of mortality among birds and mammals. Most of this carnage is caused by free-ranging stray cats, but even if we use the researchers' low ball estimates, it is nearly certain that pet cats are responsible for at least a couple of billion of these deaths.
The moral burden of cat ownership can fall particularly hard on animal protectionists. Take, for example, a recent conversation I had with a young woman I will call Jessie. She believes killing animals because they taste good is immoral; she is a vegan and consumes no meat or dairy products. She does, however, live with four pet cats. She tried feeding them vegetarian cat food, but, unsurprisingly, her pets hated it.
She has reverted to feeding them canned food and the moral burden of their diet weighs heavily on her. It should. At two ounces of meat a day, her cats will collectively eat one and a half tons of meat over their life spans.
Jessie could, of course, reduce the moral costs of feline companionship by keeping her cats indoors. While her pets would still dine on canned flesh, forcing them to live inside would reduce the damage to her neighborhood wildlife. The problem, she told me, is that her cats love the outdoors. She gets depressed when she sees them sitting in the window, wistfully looking out at the birds flitting by.
"A Cat's Gotta Kill"
I agree with her. That's why, like most cat lovers, I don't force Tilly to spend her life in the big cage I call my house. Indeed, one of the arguments made against zoos and factory farms is that they do not allow animals to exhibit their natural behaviors. The animal rights philosopher Bernard Rollin, for example, argues we have an obligation to respect an animal's telos, that is, its essence or purpose. As Rollin puts it, "fish gotta swim, birds gotta fly". I suppose, by this logic, "cats gotta kill."
Jessie is facing a no-win situation. Her commitment to animal liberation has caused her to change the clothes she wears and the food she eats ... yet, she's completely devoted to four stone-cold killers. Her choice: learn to live with inconsistency or say goodbye to the kitties.
The existence of millions of feral cats in Europe and the U.S. pose a similar set of bad choices. Unowned cats, it seems, are, by far, the largest cause of the decimation of birds and small mammal populations. An obvious solution would be to simply kill feral cats on sight. But would reducing the number of free-ranging cats actually increase native bird and mammal populations?
Possibly. In a natural experiment, two ecologists, Kevin Crooks and Michael Soulé, studied the interactions between cats and their predators, coyotes, on bird populations in the urban ravines of southern California. Having a coyote in the neighborhood significantly reduced the number of cats. (Indeed, 25 percent of cats they radio-collared were eaten by coyotes.) More importantly, having a cat-killing predator around the neighborhood increased the number and diversity of birds flying around urban backyards.
Predatory Pets: No Easy Answers
Putting a bounty on feral cats would, of course, be unacceptable to the millions of Americans who are cat lovers. (I am one of them.) An alternative cat reduction strategy has emerged in recent years -- "trap-neuter-return" programs, in which free-ranging cats are captured, neutered, and set free. Often these animals live in groups under loose human supervision. As you might expect, bird enthusiasts are not happy with the proliferation of these "cat colonies", and indeed, a recent survey found that cat colony caretakers and bird conservation professionals live in completely different moral worlds when it comes to the value of cats and birds. For example, while 90 percent of birders believed that feral cats contribute to the decline of native birds, only 20 percent of cat-advocates agreed that cats were major bird killers. (See, for example, this rebuttal to the Nature Communications article.)
The birders, however, are probably right. "Trap-neuter-return" programs may eventually reduce the numbers of free-ranging cats, but studies suggest they will probably take decades to have an appreciable impact. In the meantime, billions of wild birds and mammals will die and some species will become extinct.
Jessie is faced with the prospects of either getting rid of her beloved pets or living in violation of her convictions. The existence of millions of feral killing machines in America's alleyways and backyards poses an equally unpalatable dilemma.