Historically, farms kept cats to take care of rats hanging around the barn. Every brewery had at least one “grain cat.” Inner-city commercial businesses, suburban warehouses, even rural dumps encouraged the presence of cats, thinking that the cats would get rid of rodents without poisons or expense. Seems that cats, being cats, have been putting one over on us all this time!

Rats caught on NightCam at a Colonial Pest site. Z. Ciras

Fordham University ecologist Michael Parsons was studying how rat pheromones influence other rats, when feral cats interfered by moving into his study site, a rat-infested recycling facility in Brooklyn, NY. Since he couldn’t get the cats to leave, he tweaked his research and began studying the interactions between 100 resident rats and the feral cats. His team set up cameras, fitted rats with microchips, and studied more than 300 resulting videos taken over 79 days.

WHO KNEW? RATS AND CATS RESPECT EACH OTHER!

While there have been studies on the impact of cats on birds and native wildlife, little attention has been paid to the impact of cats on rats, especially city rats. Here, briefly, is some of what the researchers found:

• The cats didn’t bother the rats at all out in the open. It was rare to see a rat-cat interaction. Of the hundreds of videos viewed, there were only 20 stalking events and three kill attempts, with only two rats actually killed, ambush-style, when they were found in hiding.
• When rats detected the scent of cats, they would carefully investigate and would tend to avoid the area in the future. In the presence of cats, rats did seem to be more wary when moving about, and about 20% of the time they would seek shelter if they saw a cat.
• Rats adjusted their behavior around the cats, spending less time out in the open and more time in their burrows. Rats would wait out a stalking cat and when it finally left the scene, it was back to business as usual for the rats.
• The researchers concluded that, while the feral cats changed rat behavior, they had no real effect on the rat population. Releasing cats for the purpose of rat control is more likely to pose a risk to birds and other local wildlife.

CATS PREFER SMALLER, LESS TOOTHY PREY

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Usually, a mature rat is just a little too much for the average cat to handle, where a mouse or bird will do nicely. Whether a cat will go after a rat probably depends on the size of each, just how pampered or street-savvy the cat is, and how hungry the cat is. In this case, since neither the cats nor the rats really wanted to interact with each other, they tended to just get along, dividing up the available space and resources.

Perhaps groups that advocate turning feral cats loose in cities to fight rodents (for example, Blue Collar Cats, in D.C. and Cats at Work, in Chicago) need to rethink their premise. While cats might help some with mice on a property, and maybe even young rats, don’t expect them to make much of an impact on resident rats. Parsons says that when people credit cats with seeing fewer rats on a property, it’s less likely that the rats were killed and more likely that the rats just changed their behavior.

This is all good news for pest management professionals. You still need us! We’re waiting for your call – 1-800-525-8084.

For more on rats:

• 10 Reasons Why Rats Creep Us Out!
• Are You Sharing Your Yard with Rats?
• Manage Food and Garbage to Manage Rats