More playtime and meatier meals might reduce kitty kills

Sometimes, conserving wildlife can be as simple as playing with a cat. Pet cats can be predators of wildlife. But giving cats a meat-rich diet or a few minutes of hunting-like play each day will cut the amount of wildlife they bring home. That’s the finding of a new study. The tactic is fun for the cat — so it’s something pet owners are more likely to try.

No one knows the exact number, but it’s likely that billions of birds and mammals end up in the jaws of outdoor cats. Cats can’t hunt if they’re kept indoors. But many owners like to let their cats enjoy nature. Colorful collars or loud bells might make outdoor cats more noticeable — and less dangerous — to their prey. But the cats themselves might object.

So it’s important to come to with methods that reduce predation by cats and have buy-in from pet owners. Interventions “are so important because we’re just decimating bird populations,” says Susan Willson at St. Lawrence University in Canton, N.Y. She wasn’t involved in the study but is an ecologist. While this study is preliminary, she says it shows that “simply feeding your cat a high-meat diet might actually work.”

Most attempts to reduce cats’ wildlife-hunting have focused on restricting cat behavior. Robbie McDonald and his colleagues studied the root of the problem — the cats’ urge to hunt in the first place. McDonald is an ecologist at the University of Exeter in Cornwall, England.

“We wanted to find out why well-fed cats might still kill wildlife,” he says. His team thought this urge might stem from natural instincts to hunt. It might also reflect a need for cats to supplement their diet. As carnivores, cats need to eat meat. Some pet foods might not meet all a cat’s needs, McDonald says. If diet or instincts influence hunting, perhaps beefing up the meat in a cat’s diet or mimicking hunting behavior through play could satisfy their needs. Then, the cats might leave wildlife alone.

More play, less prey

To test this, McDonald and his colleagues recruited 355 outdoor domestic cats from 219 households in southwest England. They enrolled only cats with known hunting skills. First, the owners counted every bird, mammal or other critter their cats brought home for seven weeks. This established a baseline for each cat.

Owners then tried one of a handful of interventions for the next six weeks. Thirty-nine owners switched to a high-meat cat food. Forty-six others played with their kitties for five to 10 minutes each day. Another group of 38 owners put their cat’s normal food in a puzzle feeder — a ball that the cat had to bat around before the food fell out. Other owners changed what their cats wore: 33 owners put bells on their cats and 31 fastened Birdsbesafe collars around their necks. These big rainbow-clown collars have been designed to stand out to birds. Finally, 32 owners didn’t do anything different.

All owners then continued to track how many prey animals their cats brought home.

Cats fed the meat-rich diet brought home 36 percent less prey, on average, than at baseline, the team found. For instance, a cat that normally brought home 30 critters per month might bring home only 20. “This might not seem like very much,” McDonald says. But a small drop in hunting, he says, could make a big difference when you think about the billions of prey that outdoor cats kill each year.

Some felines got extra playtime. Their owners got them to stalk, chase and pounce on a feather toy. Then, they gave the cats a mouse toy to bite — rewarding them for “catching” their prey. The playful cats brought home 25 percent less prey. That drop came mostly from mammals (like mice), not birds. Cats that started using puzzle feeders actually brought home more prey. Collars with bells had no effect on hunting. Finally, cats wearing Birdsbesafe collars brought home 42 percent fewer birds, but roughly the same number of mammals. That fits with previous research on the collars.

McDonald’s group published its findings February 11 in Current Biology.

Making sense of the ‘take home’ findings

“We were surprised diet change had such a strong effect,” McDonald says. Before the study, the cats had all eaten different things. Some might, therefore, have had a meatier diet to start with. He now concludes “nutrition seems to have some bearing on a cat’s tendency to kill things.” Some cats that kill a lot might be hunting for a few nutrients their diet isn’t providing. McDonald already is working to pinpoint what that extra something might be.

“It’s a robust study that I hope is followed up with more research,” says Willson, the St. Lawrence ecologist. But she also notes the study focused on prey brought home. So it could be missing some wildlife, she points out. Cats might kill and eat some animals, or leave others outside. Those wouldn’t be counted in this study.

The surest way to prevent cats from killing wildlife is to keep them indoors, McDonald says. While many cat owners care about wildlife, some view keeping cats inside as unnatural. Adding meaty diets and increasing playtime are less controversial, he notes. After the trial, one-third of people who gave their cats meaty food reported they planned to continue giving their cats meat-rich diets. In the play group, 76 percent reported they’d keep giving their cat bonus playtime. 

“We hope that owners of cats who hunt consider trying these changes,” McDonald says. “It’s good for conservation and good for cats.”