It’s a Cat-astrophe

A new report in Nature suggests that domestic cats, primarily un-owned, are responsible for an estimated 6.9 to 20.7 billion animal deaths every year. While the majority of animals killed were by strays, feral and farm cats, a significant number were from pet cats.

Here we conduct a systematic review and quantitatively estimate mortality caused by cats in the United States. We estimate that free-ranging domestic cats kill 1.4–3.7 billion birds and 6.9–20.7 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of   this   mortality.   Our findings   suggest   that   free-ranging cats   cause   substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals.

cats kill wildlife nature

This number is comparable to the nine billion chickens that are eaten every year in the US. To put it in further perspective, this is 250 – 800 times the number of animals used each year in the US for medical research. To put it another way, in 2013, cats will kill a larger number of animals in one year than have ever been used in research in the US.

We have already pointed out that food, hunting and driving are all activities responsible for far more animal suffering than animal research.

Animals in Food, Hunting and Research

The timing of this report coincidentally came a few days after the animal rights activist, Rick Bogle, wrote an article where he discussed whether or not we could measure, in a comparable way, different types of animal suffering. Bogle’s objective was to show that animal research would be more cruel than many other common deaths suffered by animals. He notes:

The suffering of a squirrel who darts out in front of a car and is hit might be as horrible as the suffering of a rat whose spine has been crushed in a lab, but on a cruelty scale, a scale of hideousness, they do not seem to be very similar.

Bogle, as usual, neglects to mention that any research studying spinal damage could only legally occur if the animal was anaesthetised. Furthermore, such experiments would offer hope to the many humans and pets who suffer paralysis from spinal injuries. He also fails to acknowledge that many squirrels hit by a car are not killed outright, and, whereas a suffering animal in a lab will be put down, nature has no such compassion.

Bogle also picks examples of animal suffering that are linked to human activity, choosing not to mention the rampant bloodshed that occurs in nature. Few non-domestic animals in their natural settings will live to old age; instead they will be finished by starvation, predation or disease. The many mice and birds killed by cats (not to mention those who escape injured), will suffer considerably more than in almost any lab experiment.

Put together, we can see an absurdity in any animal rights philosophy which gives animals a right not to suffer. Such a right would entail human intervention to prevent it – not just an abatement of our uses of animals, but a war on nature itself.

Tom Holder

Loss, S.R., Will, T. & Marra P.P., 2013. “The impact of free-ranging domestic cats on wildlife of the United States” in Nature Communications.

5 responses to “It’s a Cat-astrophe

  1. Some of the figure images are missing, but I love the post!

  2. From the Arctic to the Antarctic the Americas have indigenous small cats and foxes that eat rodents and birds. Rodents are also destructive to birds, particularly their eggs and young. There is no “anthropogenic” problem here. The imported species of cats are very similar to the original species. Perhaps “Nature” needs a better review process.

  3. Thank for the edit note – all sorted (i think)

  4. All that the “domestic” cats have done is replace the predators that were here before.

  5. First of all, anyone who writes about this latest round in the Tweety & Sylvester wars without looking first at the evaluations of the input data by Peter Wolf of Vox Felina is not doing adequate research.

    Peter Wolf knows all of the relevant studies worldwide more thoroughly than anyone else ever has, even the late Ellen Perry Berkeley, who started out around 30 years ago as an avid birder who wanted to understand the ecological effects of feral cats, & ended up as a feral cat advocate.

    Reporters tend to quote the Tweety & Sylvester partisans, notably the American Bird Conservancy and their friends in government, and on the other side of the fence, Alley Cat Allies & local feral cat neuter/return advocates, but tend to overlook taking a critical look at the alleged science, as Wolf has made a vocation of doing.

    Peter Wolf has already noticed some huge holes in the projected data behind the Smithsonian Migratory Bird Center/USFWS paper that ABC is trumpeting this morning, including some identified by the researchers themselves in other papers. I just received his preliminary critique, & expect he’ll be willing to share it with anyone else who asks, ℅ .

    Second, there are a lot of completely bogus numbers & theories about the numbers of feral & other outdoor cats, but this really should not be a mystery to people who do their homework, & the numbers over the past century have actually been remarkably consistent.

    In truth, the U.S. outdoor cat population has not significantly changed in more than 15 years, as measured by shelter intakes, roadkill counts, surveys of cat rescuers, and habitat studies. Before that, it rose for a few decades & then plummeted very rapidly in the early 1990s, coinciding with the introduction of neuter/return. Neuter/return had a huge impact for about 10 years, but then apparently reached the limits of what neuter/return practitioners could do in the places they could go with the resources available.

    The present U.S. cat population breaks down to about 74 million total pet cats (AVMA Sourcebook 2012), of whom about 50 million are kept entirely indoors, while 24 million spend part or all of their time outdoors.

    There are presently about 6.5 million feral cats at winter low each year, with 12 to 13 million at summer high.

    The total number of cats is just over 90 million, or about the same as the total number of pet cats alone in 2007 (again as reported by the AVMA Sourcebook) At that time, ferals included, the total number of cats sometimes topped 100 million.

    The U.S. cat population in 1991 broke down to about 40 million indoor pet cats, plus about 20 million pet cats who spent all or part of their time outdoors, & about 20 million feral cats at winter low, rising to 40 million at summer peak, of whom about half were kittens, half of whom would not survive to weaning. That was the all-time high. The year-round average was about 26 million.

    The total U.S. cat population in 1950, according to the “John Marbanks” studies done by National Family Opinion founders Howard & Clara Trumbull, was circa 35 million, with almost no full-time indoor cats.

    The Trumbulls had discovered similar numbers in 1927 and 1937, with a shift from feral or stray cats to fed pet cats.

    Earlier, circa 1908, Frank M. Chapman of the American Museum of Natural History estimated that there were 25 million total cats in the U.S.

    So, what we have documeted is that the outdoor portion of the cat population, pets & stray/feral combined, has done this on year-round average:

    1908 1927 1937 1950 (gap) 1991 2003 2012

    25m 30m 30m 35m 46m 36m 36m

    That’s astonishingly steady compared to human populations, wildlife populations, & any other animal populations on record.

    Third, it is critical to note that most of the controversy associated with specific neuter/return projects originates not from the neuter/return work itself, but rather from the behavior of the cat-feeders who are often enlisted to help trap the cats and monitor their population.

    It is the feeders, not the people who actually do neuter/return, who often encourage furtive, nocturnal rodent-hunting cats who seldom see birds, let alone hunt them, to become well-fed diurnal sport hunters — who begin hitting more birds because more birds are around in the daytime.

    Feeding the cats is not actually a necessary component of neuter/return. The cats have adequate food sources without the feeders, or the cats would not be where they are in the first place. But cat-feeders are as ubiquitous and problematic as pigeon-feeders & backyard songbird feeders, for that matter, who often feed most of the squirrels and rats in the vicinity as well as the birds.

    It is instinctive for anyone who wants to help or befriend any person or animal to offer food, & then the Law of Unintended Consequence comes into effect.