Purr-fect threat: Are cats a danger to Earth’s biodiversity?

Few animals are so polarising as Felis catus, the domesticated cat. As companion animals they’re beloved, practically a spirit animal for the 21st century; when ranging freely they’re the scourge of many conservationists, who lament the impact of their predation on biodiversity.

Might some of that lamentation be overestimated, even hyperbolic? Or, conversely, are cat defenders guilty of science denialism and the willful spread of disinformation?

For the past several years this debate has simmered in public discussions, news media and scientific press, with the latest installment appearing in the high-profile journal Conservation Biology. In an article entitled “A moral panic over cats,” a group of scholars and researchers led by ethicist Bill Lynn of Clark University and anthropologist Barbara King of the College of William and Mary argue that people who see cat issues in shades of grey rather than black-and-white certainties have been unfairly vilified.

“Some conservationists believe free-ranging cats pose an enormous risk to biodiversity and public health and therefore should be eliminated from the landscape by any means necessary. They further claim that those who question the science or ethics behind their arguments are science deniers,” they write. “As much as we share a commitment to conservation biodiversity and wild nature, we believe these ideas are wrong and fuel an unwarranted moral panic over cats.”

The phrase “by any means necessary” is a reference to Cat Wars, a 2016 book by Peter Marra, a Smithsonian Institute bird conservationist. “From a conservation ecology perspective, the most desirable solution seems clear – remove all free-ranging cats from the landscape by any means necessary,” he wrote. In 2013, Marra and Scott Loss, an ecologist at Oklahoma State University, had reviewed dozens of studies on predation by free-ranging cats, arriving at the most rigorous estimate to date of free-ranging cat predation: between 1.3 and 4.0 billion birds killed annually in the continental United States, along with between 6.3 and 22.3 billion mammals.

Beware the cat

Some cat advocacy organisations, most notably Alley Cat Allies, criticised the methods used to make those estimates. Marra and Loss replied with a point-by-point rebuttal of those criticisms, published late last year in Biological Invasions, and a Conservation Biology paper entitled “Merchants of doubt in the free‐ranging cat conflict.” In the latter, they wrote that “campaigns to fabricate doubt about cat impacts have entered conservation science,” and opined that the “misinformation strategies of free-ranging cat advocates strikingly duplicate past approaches of cigarette and climate-change fact fighters.”

In the latest paper, Lynn and King and colleagues acknowledge that cats can harm biodiversity and that scepticism “should not be used to deny the impact cats may have when rigorously documented for specific contexts.” Yet the charge of denialism, they say, is unwarranted, and makes it easy to ignore legitimate disagreements over how free-ranging cats are portrayed: not about whether they do eat billions of small animals, which is clearly the case, but about the ecological impacts of this predation and how to address it without demonising felines.

Marra and Loss have argued that free-ranging cats are an imminent danger to public health, for example, because they might spread toxoplasmosis and rabies. Yet that threat is arguably exaggerated and could lead people to regard many other species as threats. Even some of the animals conservationists hope to protect against cats may carry pathogens of concern: Shorebirds carry influenza, and some songbirds host Lyme disease-transmitting ticks.

As for the impact of cats, Lynn and King’s team say these vary depending on habitat and ecological context. Cat predation within small islands or a pocket urban forest may affect populations of prey species differently than at the edges of large natural areas. And while trap-neuter-return programs, the favored approach of cat advocates to free-ranging cats, are not always effective, they can work when done rigorously.

Feline debate

The effectiveness of lethal cat control programs – the implicit end result of a by-any-means-necessary mentality – is also mixed. Often they don’t decrease cat numbers or achieve desired outcomes. Even conservationists who have few qualms about killing cats sometimes feel that culls are band-aid solutions that forestall engagement with other, more-pressing problems, as with Australia’s controversial plan to kill two million free-ranging cats even as habitat destruction continues at a torrid pace.

Then come the ethics of killing cats. King and Lynn and several of the new paper’s authors are what’s known as “compassionate conservationists,” who argue that killing animals for conservation purposes is either completely unacceptable or justified only as a last resort. Some think wild, free-ranging cats should even be accepted as a legitimate members of their ecosystems. Not everyone subscribes to those values, but the possibility of a public relations backlash –the inevitable photos of people posing triumphantly with dead cats, videos of poisoned felines writhing for hours – and subsequent erosion of public support for conservation is very real.

Wayne Linklater, an ecologist at the Victoria University of Wellington in New Zealand who was not involved in this latest paper, called it “an important and comprehensive rebuke to allegations of science denialism about cats.” Linklater has written about the importance of building relationships between cat people and conservationists. Marra and Loss have likewise called for more inclusive conversations; King and Lynn’s team echo that.

“We urge everyone concerned with free-ranging cats to reject framing this debate as a matter of us versus them,” they write – and on that, perhaps, conservationists and cat people alike can find common ground.

This article first appeared on Anthropocene Magazine.