Cat Track Fever

Is your cat cheating on you? These private eyes will help you find out (and protect native wildlife in the process).

November 10, 2014

Banjo came home smelling of cigarettes and perfume, never divulging where he’d been. Sheba* was supposedly dieting but somehow never shed a pound. Cowardly Chicha, her loved ones assumed, would never stray.

Intrigue—and in some cases, twinges of jealousy—drove their families to take bold action: They forced the trio to wear harnesses with GPS units that tracked their every move. Banjo, Sheba, and Chicha were powerless to resist, since they’re cats.

The owners’ curiosity may have killed the cats’ privacy, but their participation in the citizen science project Cat Tracker is for a greater good. In the United States there are an estimated 95 million pet cats, and about half as many feral felines. These furballs may look sweet, but free-ranging cats kill 1.3 billion to 4 billion birds and 6.3 billion to 22.3 billion mammals annually, researchers reported in Nature Communications last year. While feral cats are thought to do the majority of the killing, nobody has conducted a large-scale study to figure out exactly how much damage Tigger and his well-fed pals are doing.

That’s where Cat Tracker comes in. Across the United States, nearly 400 people have signed up (the goal is 1,000) for this program that’s helping map the movement of domesticated cats. Some participants are also sending in their cat’s fecal samples; DNA analysis will reveal what Mr. Whiskers has been eating and whether he’s bringing home any harmful parasites.

“The big question is, How much ecological impact do cats have on native prey, where is this impact happening, and what factors affect it,” like the animals’ age or sex, the presence or absence of other predators, or whether they live in an urban or rural environment, says Roland Kays, the project leader and director of the Biodiversity Lab at the North Carolina Museum of Natural Sciences.

Photo: Cat TrackerThe Cat Tracker harness.

Kays has decades of experience tracking everything from kinkajous and orchid bees in Panama to lions in Kenya to fishers in New York. “Cats are a lot easier to catch,” he says. “Seriously. If you want to study wild animals, catching them is often the hardest part.” Pet cats are easy to snag, and the team can reuse the GPS tags, which cost $50 each, over and over again, reducing costs.

Kays’ team includes Troi Perkins and Riana Gayle, two North Carolina State undergrads who are responsible for drumming up and training participants. They put the word out on social media, reached a few people in the cat-fancying community, “and more and more people started signing up,” says Perkins. “It just kind of snowballs.” (Note: No cats named Snowball have taken part in the project, but Donald Fluffypants, Psycho Kitty, Captain America, and Boris have all done their time in the harness.)

Perkins trains participants in the Raleigh-Durham area, helping the owners place the H-style contraption on their reluctant pets. “Lots of cats, when you put the harness on, you get this freeze, then flop effect,” she says. “Or they’ll do this funny scoot, backing up and trying to get out of the harness. One cat ran up the wall and did a backflip. She was totally fine. She looked around and was like, What is this thing on me?”

The cats get 24 hours to get used to the harness before the GPS unit is turned on. After ten days of tracking, Perkins picks up the unit and downloads the data before passing it along to the next participant. (There’s also a DIY option: People can purchase the spy gear themselves, then upload the data to

Photo: Cat TrackerA map showing one Cat Tracker cat's movements over the course of one week.

So far the researchers have seen that most cats remain within a block or so of their house. In two-cat households, one feline tends to stick closer to home, while the other roams a bit more widely. “By and large, they don’t venture into woods or preserves; they stay on borders,” says Perkins. “We’re thinking it might be due to coyotes, because they’re so rampant, at least around Raleigh-Durham.”

Gayle, who oversees the Long Island, New York, arm of the study, is examining what cat movements look like in the absence of those canine predators. “Long Island is the only large chunk of land in North America where coyotes aren’t established yet,” she says. “We want to see how that affects the cats’ home ranges. Are they venturing out more, are they more adventurous when there are no predators?”

Once 1,000 cats have been tracked, the researchers will analyze all the data and see what trends they can pounce on. But owners can find out what kitty has been up to right away, with a map that Perkins e-mails them within a day of removing the harness. They’re always excited, says Perkins, though sometimes they do feel shock or betrayal. “There’s a lot of talk about cats cheating on their owners.”

In the case of Banjo, he stopped stepping out on his family before the project started and turned out to be a homebody. Sheba, the one on a diet, was revealed to be, well, a cat burglar: She was sneaking over to a neighboring cat’s house and stealing its food. As for Chicha, the supposed ‘fraidy cat, she did stick close to home—until her owners went away for the weekend. Chicha upped and left, too. The data showed that she traveled nearly a mile. Her owners were incredulous until they looked at the map and saw that she’d gone back to the house they’d moved out of years before. Domestic cats, it seems, might have long-term spatial memory. “The more cats we map,” says Perkins, “the more surprises we see.”

*Sheba’s name has been changed to protect the thieving fat cat’s identity.  

onEarth provides reporting and analysis about environmental science, policy, and culture. All opinions expressed are those of the authors and do not necessarily reflect the policies or positions of NRDC. Learn more or follow us on Facebook and Twitter.

Join Us

When you sign up you'll become a member of NRDC's Activist Network. We will keep you informed with the latest alerts and progress reports.