Sorry, Cat Lovers: Trap-Neuter-Return Simply Doesn't Work

If animal welfare advocates are genuinely against killing animals—and if they believe in protecting public health—they need to be against TNR.
(Photo: Shaun Lowe/Getty Images)
Apr 1, 2014· 3 MIN READ
Richard Conniff is the author of House of Lost Worlds: Dinosaurs, Dynasties, and the Story of Life on Earth and other books.

Various estimates say that anywhere from 20 million to 100 million feral cats roam the United States. Together with pet cats that are allowed to wander free, they kill billions of birds, mammals, and other animals every year.

Every time I write about the need to deal with this rapidly worsening problem, certain readers argue for a method called TNR, which stands for “trap-neuter-return,” or sometimes “trap-neuter-release.” So let’s take a look at how it might work.

TNR is an idea with enormous appeal for many animal welfare organizations, because it means cat shelters no longer have to euthanize unwanted cats: They just neuter and immunize them, then ship them back out into the world. It’s a way to avoid the deeply dispiriting business of putting animals down, not to mention the expense of feeding and caring for the animals during the usual waiting period for a possible adoption. And it enables animal shelters to put on a happier face for donors: “We’re a shelter, not a slaughterhouse.”

TNR advocates generally cite a handful of studies as evidence that this method works. The pick of the litter is a 2003 study that supporters say shows TNR enabled the University of Central Florida to reduce the feral cat population on its Orlando campus by 66 percent. On closer examination, though, what that study showed was that 47 percent of the cat population was removed through an intensive adoption program, another 11 percent was euthanized, and at least another 6 percent was killed by automobiles or moved off campus to nearby woods. TNR itself appears to have accomplished almost nothing—and it took 11 years to do it.

By email, the lead author of that study, Julie K. Levy, told me that adoption is a common component of TNR programs. She added, “I’d hate to speculate about what the outcome would have been without some cat removal, as that introduces a lot of uncountable variables.” But Levy, who remains a TNR advocate, was part of a team that subsequently examined just that question in two large-scale TNR programs in San Diego County, Calif., and Alachua County, Fla. She and her coauthors found that “any population-level effects” from TNR alone “were minimal.”

The programs might have been effective, the coauthors suggested, if they had neutered 71 to 94 percent of all feral cats, but that rate is “far greater than what was actually achieved.” It is, in fact, far greater than almost any TNR program ever achieves, because, as Levy has written more recently, “capturing free-roaming cats, transporting them to a central facility for sterilization, and returning them to the trapping site are resource-intensive activities” and “challenging to sustain.”

TNR advocates also frequently cite a large-scale program on 103 cat colonies in Rome. Trapping and neutering decreased the populations of 55 cat colonies there, while the other 48 colonies either gained population or stayed the same. The authors of that study concluded that, in the absence of a public education campaign to stop people from abandoning cats, “all these efforts” are “a waste of money, time and energy.”

Yet TNR proponents just go on touting the same evidence, with an almost magical faith that it will somehow turn out to support their almost religious beliefs. They do this, I think, because anyone who has seen a pet die knows how emotionally devastating it can be. Twice in my life, I’ve been the person who delivered a pet to the veterinarian to be, as the euphemism has it, “put to sleep.” They rank among the worst days of my life. But both deaths were quick and painless, a matter of falling asleep on my lap, and in both those cases it was infinitely better for the animal than to go on living with disease and impairment.

That’s the choice TNR advocates refuse to make. They see only the individual cat saved from euthanasia and willfully blind themselves to the consequences for the cat itself and for everyone else. When they cite the Rome study as a success story, for instance, they neglect to note that Italy doesn’t have rabies. In this country, on the other hand, rabies prevention efforts cost $300 million a year, and 40,000 people must receive treatment after being bitten or scratched.

Cats are three to four times more likely than dogs to have rabies, and yet TNR programs inevitably leave a significant percentage of feral cats on the street, untreated, for years at a time, aggravating the rabies problem and numerous other diseases of both cats and humans. Because of the threat to public health, most communities have laws preventing individuals from hoarding animals even in the privacy of their homes. But as the authors of one recent article on cat-borne diseases put it, TNR “is essentially cat hoarding without walls.”

The cats in TNR programs also go on killing. Let’s say each cat kills 30 birds a year, and the local TNR program has a population of 100 cats. Over a 10-year period, that program has made itself an accessory to 30,000 unnecessary deaths. (Yes, I’m assuming that the population stays the same. That’s because a lot of TNR programs explicitly aim “to maintain stable cat populations.”) TNR advocates see the cat deaths as individual tragedies. But birds somehow just die as populations, or species. Because the cats do their killing out of our sight, and without our direct intervention, people fail to see that those other deaths are equally individual, and—because cats like to have their fun—far more cruel.

Despite all this, TNR continues to gain popularity. It could well show up next in your community. Politicians like how it sounds to be against killing, so they are easy targets for TNR advocates driven by an extremely narrow definition of “animal welfare.” Be prepared to stand up and remind community leaders that if they are genuinely against killing animals—and if they believe in protecting public health—they need to be against TNR.