The Benefits of Keeping Cats Indoors: Protecting Biodiversity and Ensuring Cat Safety

Cats evolved outdoors, and it makes sense that as their primary caretakers, we should let them explore outside as much as possible. However, as counterintuitive as it may seem, keeping your cats indoors may be the better option—both for them and to preserve local biodiversity.

Cats are natural hunters, and most cannot resist this instinct when kept outdoors—no matter how well they’re being fed. A recent study by the University of Maryland (UMD) has shown that keeping your cat indoors can significantly reduce the impact on native biodiversity and small animal populations. Not only that, but they found that being outdoors can pose a significant risk to your feline, too—rabies, toxoplasmosis, and other diseases are real risks for outdoor felines.

But are cats really better off when kept indoors?

Considering a cat’s natural instincts to climb, explore, and hunt, it’s easy to feel sympathy for cats who are “locked away” inside. But the truth is that they’re simply at more risk of catching diseases and wreaking devastation on local wildlife when allowed to roam freely outdoors. According to the latest available data, cats in the US kill an astonishing 2.4 billion birds a year—and that’s just birds. If we include small mammals, the numbers are even more shocking.

Dr. Paola Cuevas, a veterinarian at Excitedcats.com, adds that “as cute as your cat might look, never forget that your cat is a predator by instinct and evolution. This predatory instinct is so strong that some cats will kill even if they don’t necessarily plan to eat their prey. In an era where biodiversity is being lost by the minute, we need responsible cat owners to actively help us preserve wild species proactively.”

Indeed, the responsibility to keep cats as safe as possible, plus protect local biodiversity, is solely up to their owners. According to the same UMD study, in which the researchers analyzed data provided by D.C. Cat Count, the team used data from 60 motion-activated wildlife cameras spread across 1,500 sampling locations and discovered that an average domestic cat in Washington D.C. has more than 60% probability of being in close proximity to raccoons. These animals happen to be one of the most prolific rabies vectors in the US. The numbers are similar with red foxes and slightly lower at 56% for opossums, both of which can also spread the virus. This means that giving your cat the freedom to roam outdoors also comes with risks of its own.

The study scans a comprehensive area and makes these numbers all the more alarming.

The same team found that when cats roam freely outdoors they share spaces with dozens of small mammals—squirrels, chipmunks, various birds, mice, and rabbits, to name but a few. When these animals are hunted and killed by cats, it can have a devastating effect on biodiversity and cause a chain reaction that affects a handful of other predators, ultimately harming the local ecosystem. With the sheer number of domestic cats in the US—around 42 million in US households and over 70 million feral or unowned (and counting)—the common argument that these cats are simply “taking up their natural role in the ecosystem” is being disputed more frequently than ever.

The premise of the study uses simple, easy-to-understand metrics that urge owners to keep their cats indoors—as much as possible, at least. There are many ways to keep indoor cats happy—using toys, cat trees, and even window boxes that give them a view of the outside world and safe, fenced-in outdoor play areas. Dr. Cuevas agrees. “Cat enclosures allow your cat to enjoy the sensorial enrichment that the outdoors provide; they allow a space for the cat to display natural behaviors without becoming a threat to others.”