Nature Communications – Pain In The Bud

The Literary Hub story starts off with a provocative question: what if cats ruled the world?

This is a question I find amusing to ponder, so instantly my mind was filled with images of cats scandalizing foreign heads of state by insouciantly swiping gifts off tables, angering diplomats by yawning and nodding off during summits, and financing the construction of massive and unnecessary coastal walls, on the off chance the ocean decides to move inland and get them wet.

Then the writer cited the repeatedly-debunked “study” that credulous media of all stripes still reference without bothering to read the text — that infamous 2013 Nature Communications paper, published by birders who author books with titles like “Cat Wars: The Consequences Of A Cuddly Killer.”

Some journalists don’t know any better, some are overworked, and some are frankly too lazy to read the study with a critical eye, but I think one of the more likely reasons people continue to cite the paper is because it’s easier to blame felinekind for wildlife extirpation than it is to admit we’re the primary culprits. After all, according to the WWF’s most recent annual review, we’ve killed off 73 percent of Earth’s wildlife since 1970, and we certainly didn’t need house cats to help us push elephants, rhinos, every species of higher non-human primate, and innumerable other species to the brink of extinction.

We did that. We did it with our relentless development, consuming and fracturing wild habitats. We did it with careless industrialization, by dumping chemicals and garbage into our rivers and lakes until more than half of them were rendered too polluted to swim in or drink from. We did it by bulldozing old growth forest and jungle, by exploiting species for fur, folk medicine, ivory, sport hunting and in the illegal wildlife trade.

Cheetahs are critically endangered, and they’re being driven to extinction even faster by poachers, who sell them to wealthy buyers in oil-rich gulf states where they’re trendy pets. Credit: Riccardo Parretti/Pexels

More than 47,000 species — that we know of — are headed toward extinction. It’s so much easier to blame it on anyone or anything else than admit we need to make major changes to our lifestyles and policies.

But don’t take my word for it. Here’s what Alley Cat Allies has to say about the 2013 meta-analysis and its derivative papers:

“The Smithsonian-funded study published in Nature Communications is not rigorous science.
It is a literature review that surveys a variety of unrelated, older studies and concocts a highly speculative conclusion that suits the researchers’ seemingly desperate anti-cat agenda. This speculative research is highly dangerous. It is being used by opponents of outdoor cats and Trap-Neuter-Return (including the authors) to further an agenda to kill more cats and roll back decades of progress on TNR. And it is being spread unchecked by the media.“

Here’s what a group of ethicists and anthropologists wrote about the claims against cats in the journal Conservation Biology, lamenting the lack of nuance and danger in arguing that cats must be stopped “by any means necessary.” The drive to blame felines, they argue, has “fueled an unwarranted moral panic over cats”:

“Contrary to Loss and Marra’s claims that the scientific consensus is consistent with their views that cats are a global threat to biodiversity, the actual scientific consensus is that cats can, in certain contexts, have suppressive population-level effects on some other species (Twardek et al. 2017). This is something that is true of all predators, native or not (Wallach et al. 2010). Thus, cats should not be profiled as a general threat a priori and without reference to important factors of ecological context, situational factors, clear definition of harms, and evidence thereof.”

“There are there are serious reasons to suspect the reliability of the new, extreme cat-killer statistics,” wrote Barbara J. King, retired chairwoman of the department of anthropology at The College of William and Mary.

Feline predatory impact varies by local conditions. Free-ranging cats in cities and suburbs kill rodents, but have minimal impact on other animals, data shows. Credit: Patricia Luquet/Pexels

Like we’ve often noted here on PITB, the authors of the Nature Communications study can’t even say how many free-ranging felines exist in the US. They say it’s between 20 and 120 million. That’s a 100 million difference in the potential cat population! How can they tell us how many birds and mammals are killed by cats if they can’t even tell us how many cats there are? No amount of massaging the numbers can provide an accurate picture if the initial data is shaky or nonexistent.

Furthermore, the nature of a meta-analysis means the authors depend on earlier studies for estimates on predatory impact, but the 2013 Nature Communications paper does not include any data —not a single study — on feline predatory impact. In other words, they have no idea how many animals free-ranging cats actually kill.

In authentic studies that actually do measure predatory impact, the data varies widely in geographic and demographic context. Data derived from the D.C. Cat Count, for example, shows that cats living more than 800 feet from forested areas rarely kill wildlife, and are much more likely to kill rodents.

Those who cite the bunk study and its derivatives are “demonizing cats with shaky statistics,” King wrote, adding she was alarmed by “an unsettling degree of uncertainty in the study’s key numbers.”

Free-roaming populations are reduced when cat colonies are managed, and the animals are fed and fixed. Credit: Mia X/Pexels

Ultimately, we agree with Wayne Pacelle, former president of the Humane Society of the United States.

The meta-analysis authors “have thrown out a provocative number for cat predation totals, and their piece has been published in a highly credible publication, but they admit the study has many deficiencies. We don’t quarrel with the conclusion that the impact is big, but the numbers are informed guesswork.”

Cats do have a negative impact on wildlife, it varies according to local circumstances, and those of us who love cats have a responsibility to keep our pets indoors and help manage free-ranging populations.

But cooler heads must prevail, approaches to managing cats must be evidence-based, and the effort requires people of all kinds working together — which becomes much more difficult when agenda-driven pseudoacademics whip people into a frenzy by portraying felines as bloodthirsty, invasive monsters who need to be wiped out “by any means necessary.”

When that kind of rhetoric drives public policy, you get countries like Australia killing two million cats by air-dropping poisoned sausages, vigilantes gunning down cats with shotguns in public parks, and local governments offering cash prizes to children who shoot the most cats and kittens. Those efforts aren’t just cruel and inhuman, there’s not a shred of proof that they do a damn thing to help other species.

Solving the problem of free-ranging cats requires us to own up to our own role in species extinction and to take measured, evidence-based steps to protect vulnerable wildlife. Otherwise, we’re inflicting a whole lot of suffering on sentient creatures and accomplishing absolutely nothing.

Talk to birders, casual conservationists or anyone who says they’re worried about the ecological impact of cats on native bird and mammal populations, and without fail they’ll bring up The Study.

Yeah, that one: A 2013 study, published in Nature Communications, that claimed cats kill “billions” of prey animals each year in the U.S. alone — including 3.7 billion birds and up to 20 billion small mammals in the contiguous states.

What activists won’t acknowledge is the fact that there are fatal flaws in the research, flaws that have been repeated in a new study claiming cats kill 10 times as many small animals as wild predators.

Let’s break it down:

– The researchers don’t actually know how many animals cats are responsible for killing. Both the 2013 Nature Communications study and the 2020 Animal Conservation study rely on owner questionnaires to estimate the number of animals pet cats kill outdoors and to assign numerical scores to their cats’ “hunting skills.” In other words, the study authors are relying on people who have no idea what their cats are doing outside to give them supposedly accurate figures on how many birds, rabbits and reptiles little Fluffy and Socks kill every year. As for people evaluating the hunting skills of their cats, how exactly do they do that? Do they consult nonexistent scoreboards? Do they find a dead mouse or two and conclude that Socks is the GOAT hunter?

– The people who took the surveys were self-selected. These aren’t random samples. The questionnaires were given to people who actively volunteered to participate in the studies.

In both cases, researchers supplemented their questionnaire data with estimates of “additional” animals killed by cats. Or to put it bluntly, the research teams invented numbers and plugged them in. They’ll claim they arrived at those numbers via analysis, but again, these are studies that rely on owner questionnaires for the bulk of the predation data. Any conclusions drawn from that data are automatically suspect.
The 2013 study was centered around a meta-analysis of earlier studies, not fresh data. For the numbers they didn’t have, researchers derived figures from older published studies. For example, they added billions of “kills” to the tally and attributed those phantom kills to “unowned cats.” The problem? No one knows exactly how many stray and feral cats roam America’s streets and countrysides, a fact the research team admitted in the 2013 study: “no empirically driven estimate of un-owned cat abundance exists for the contiguous U.S.,” they wrote.
The best estimates claim between 20 million and 120 million feral and stray cats live in the contiguous U.S. That’s a spread of 100 million! How can a research team estimate how many prey animals are killed by cats when they can’t even get a fix on the cat population? The numbers matter: If there are only 20 million ferals and strays, each of them would have to kill more than 1,000 animals a year to account for the study estimates.
Headlines trumpeting the 2020 study say it’s based on GPS data, but that’s only partially true. Yes, the team used GPS data from a small number of cats belonging to self-selected study participants, but that data tells them nothing about how many animals those cats are killing. The GPS data only indicates where cats go when they wander, not what they do. In this study, as in the last, researchers relied on questionnaires, which in turn assumes cat owners have exceptional memories and can account for everything their furry friends do outdoors when no one’s watching them.

The stakes are high, as NPR noted in a story about the 2013 study: The resulting headlines are repeated as gospel in newspapers across the country and on countless news sites, which in turn influences how people feel about cats. They influence politicians and proposed laws as well, with several countries looking to ban outdoor cats.

Buddy's claws — One cat who has zero kills: “I am NOT an inept hunter! You don’t want to tangle with these talons, bro.”

Nuance, such as the 2013 study’s admission that an unknowable number of animals are killed by “collisions with man-made structures, vehicles [and] poisoning,” is usually left out of those stories.

After all, no one’s seriously proposing an end to the automobile industry despite studies claiming untold billions of animals die as roadkill annually.

A quick Google search turns up hundreds of articles with breathless headlines like To Save Birds, Should We Kill Off Cats?, The Moral Cost of Cats, and Cat Owners Turn Blind Eye To Pets’ Violence. There are alarmist books, too, like the hysterically-named Cat Wars: The Consequences of a Cuddly Killer.

In some Australian territories, authorities have open bounties offering $10 for the scalps of adult cats and $5 for the scalps of kittens. Is this what we’ve come to? Killing baby animals based on hysteria over bunk science?

“It’s virtually impossible to determine how many cats live outside, or how many spend some portion of the day outside,” Wayne Pacelle, former president of the Humane Society of the United States, told NPR at the time. The scientists “have thrown out a provocative number for cat predation totals, and their piece has been published in a highly credible publication, but they admit the study has many deficiencies. We don’t quarrel with the conclusion that the impact is big, but the numbers are informed guesswork.”

And that’s the important thing here: Instead of calling for a mass culling of cats based on wild estimates of their environmental impact, we should be working cooperatively on solutions to curb their opportunities to hunt, starting with simple measures like keeping cats indoors.

We don’t need another study with wild estimates of feline impact on small wildlife. What we need are smart plans and the will to implement them as a society.

(First image credit Earth.com. Second image credit CatsAndBirds.ca. Third photo is Buddy, the Inept Hunter.)