Domestic cats are mass killers

29 January 2013 by Akshat Rathi, posted in Research

The Oatmeal got it right. How much do cats kill? Too. Damn. Much.

A study just published in Nature Communications estimates that, in the US alone, domestic cats (owned and un-owned) could kill up to 3.7 billion birds, 20.7 billion mammals (rats, rabbits, squirrels), 800m lizards and 300m frogs every year (even lower estimates are scary: 1.4 billion birds and 6.9 billion mammals). Domestic cats are one of the worst non-native invasive species in the world, according to the lead author of the study Scott Loss, of the Smithsonian Conservation Biology Institute.

Previously it was argued that the number of cat killings was small compared to deaths caused by, say, collisions to windows, buildings or communication towers, or even habitat destruction. But this systematic study finds otherwise.

Credit: Nature Communications

Perhaps you knew this, but earlier estimates (like that of the Oatmeal) were lower. Loss remarks that it may be because those studies were not conducted with the same rigour or depth as the current study. According to Loss the new estimates indicate that cat killings are causing population decline some species. A 2011 study even recorded extinctions caused by cat killings. The study conducted on islands showed that free-ranging cats caused extinction of 33 species of birds, mammals and reptiles.

Although un-owned cats are to blame for majority of the kills, owned cats kill a substantial number too. What should ring alarm bells for policymakers is the fact that the number of owned and un-owned cats is growing rapidly across the globe. But Loss admits their estimates based on all available data are still not accurate, and more accurate calculations can only made based on better collection of data.

Methods currently in use to bring these killings under control involve trapping feral cats and sterlising them to stop their colonies from growing. Although this may seem like a good idea, there is no scientific evidence that it works. Loss says, "Management decisions [for controlling cat killings], both in the US and globally, must be informed by fine scale research that allows analysis of population responses to cats and assessment of the success of particular actions."

While cats with guns (or cats as guns) make for funny pictures, there is more truth to that image than you might think.

ReferenceLoss, Will & Marra, The impact of free-ranging domestic cats on wildlife of the United States, Nature Communications 2013.

Image not from the study. Credit: some tumblr blog.

5 Responses to “Domestic cats are mass killers”

  1. JERRY Reply | Permalink

    Cats are the best 'pest' (frogs, snskes and lizards) reducing organisms there ever was and theire behaviour should be encouraged.

    • Ptere Reply | Permalink

      "'pest' (frogs, snskes and lizards) reducing organisms"

      How are frogs pests? Lizards? Even snakes? Snakes are incredible effective at reducing the numbers of disease causing rodents. Corn snakes are invaluable to preventing crop damage from mice.

      Cats are an invasive, predatory species that kill far more than they consume. Snakes, lizards, and frogs are alredy part of the ecosystems fabric and are already balanced against. Cats are a new factor, a new predator, more akin to a viral or bacterial infection than anything. More to a point, the presence of diseases like Feline Immunodeficiency Virus means their lives are not only shortened, but often painful.

      Helping feral cats is not easing their suffering, it is creating more cats to suffer.

  2. THABO Reply | Permalink

    i agree bro, snakes, especially frogs they look slimy and disgusting. these cats should be injected with a hormone that will make them take down snakes such as the death adder, even the great african black mamba... snakes must continue to 'shoot to kill'.

  3. Peddle Reply | Permalink

    I hope some laws come out that allow us to shoot cats. That'd be awesome. It really should be done, seeing as they destroy natural ecosystems.

    When the whole world is just cats and humans? What then, guys?

    I'll answer: no plants, no crops: no food. We starve.

    Without insects, plants won't grow. Without insect population control via mammals and birds, insects starve due to overpopulation.

    Shit needs to be discussed. The discussion doesn't end here.

  4. C.D.Carney Reply | Permalink

    Cats are the perfect companions to humanity. Only we have caused more extinctions than cats and we bring them with us everywhere we go. Cats are awesome little predators, stress reducers, are pretty much self-sufficient and they conveniently go in enclosed boxes for easy removal. The saddest thing I ever saw was the feral cat colony at the Osprey Marina in SC because there were so many cats that had been abandoned there and most of them come right up to you and want to be petted. Even the raccoons there are friendly enough to come right up to you and beg. I wish I could have saved them all and given them good homes.

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