Keep Cats Inside For Their (And Others') Own Good, Say Scientists

Cats. What should we do with them: let the little guys out, or keep them inside as house pets? It’s an age-old question for cat owners, provoking strong feelings on all sides of the argument. However, a recent study has come down pretty firmly against letting your feline friends out of the house – at least, if you live in Washington DC – and not necessarily for the reasons you think. 

“We discovered that the average domestic cat in D.C. has a 61 percent probability of being found in the same space as racoons,” said Daniel Herrera, lead author of the study and Ph.D. student in the University of Maryland’s Department of Environmental Science and Technology (ENST), in a statement. They also have a “61 percent spatial overlap with red foxes, and 56 percent overlap with Virginia opossums,” he added – and that’s a big problem for our little kitty pals.

Take raccoons, for example. These trash pandas may be adorable, but they’re also “America's most prolific rabies vector,” Herrera explained. Red foxes and opossums, too, can both spread rabies – in short, Herrera said, “by letting our cats outside we are significantly jeopardizing their health.”

That’s not even touching on the more well-known reasons for keeping your cats from the great outdoors. It’s common knowledge by this point that cats are prolific hunters – sometimes with devastating consequences for local animal populations. But what you might not appreciate is how… particular these little monsters are when it comes to choosing their prey. 

Put it this way: if you’re thinking little Tibbles is doing you a favor by keeping away vermin, you’re probably wrong.

“Many people falsely think that cats are hunting non-native populations like rats, when in fact they prefer hunting small native species,” Herrera explained. “Cats are keeping rats out of sight due to fear, but there really isn't any evidence that they are controlling the non-native rodent population. The real concern is that they are decimating native populations that provide benefits to the D.C. ecosystem.”

Another misconception: cats aren’t “just another predator” slipping into a necessary role in the ecosystem, according to the study. The likelihood of finding a cat in a habitat was positively linked to human population density, rather than any of the predictors of native wildlife – in other words, it’s us moving the little hunters in, rather than them inhabiting any kind of natural niche.

“These habitat relationships suggest that the distribution of cats is largely driven by humans, rather than natural factors,” explained Travis Gallo, assistant professor in ENST and advisor to Herrera. “Since humans largely influence where cats are on the landscape, humans also dictate the degree of risk these cats encounter and the amount of harm they cause to local wildlife.”

So what’s the solution? According to Herrera, it’s simple: keep your cats indoors – especially in situations where they’re likely to interact with native wildlife populations. Remember, it’s not just for the local fieldmouse families’ sakes – Grizelda’s health and happiness might just depend on it too.

The study is published in the journal Frontiers in Ecology and Evolution.