When it comes to chasing rodents, cats are tough guys. Think of all the cartoons and nursery rhymes where mice and rats scurry away in fear when faced with the threat of those razor-sharp claws.
Aware of that fierce hunting reputation, cities often depend on feral cats to control their rat populations. They release felines into the streets, assuming Mother Nature will do her thing and the rats will be culled with a little kitty help. But a new study shows that cats don't do a good job of catching rats at all.
Recently, a team of researchers from Fordham University were studying a rat colony at a recycling plant in Brooklyn when, to their dismay, several feral cats took up residence. Deciding to make the best of the situation, the researchers set up some infrared field cameras to see how the felines and rodents would interact. They changed the focus of their study to understand how cats affect rat behaviors and movements.
Interestingly, the result wasn't the storybook chase you might expect. Over a period of five months, the cameras only captured three serious attempts where cats tried to catch rats and only two of those attempts were successful. The cameras also recorded about 20 other stalking attempts. And this was in a facility teeming with as many as 150 rats.
"Cats are not the natural enemy of rats," lead researcher Michael Parsons told New Scientist. "They prefer smaller prey."
Rats are fierce
The results confirm what rodent experts have always said. Cats are great at catching mice, but they're much less interested and much more intimidated by rats, which are larger and fiercer.
"Once rats get above a certain size, rats ignore cats and cats ignore them," Gregory Glass, a professor at the University of Florida who has studied cat and rat interactions, tells the Atlantic. "They’re not the super predator that folks have thought them to be."
Mice weigh between 20 and 35 grams (.7 to 1.2 ounces), while rats are closer to 240 grams (8.4 ounces). Plus rats have sharp incisors that can be used to inflict quite a bit of damage in a confrontation.
Despite all this, the idea that cats are a rat's natural predator persists, and cities still rely on them for predation.
"Given our results, we can only note that the public's continued confusion between rats and mice may be encouraging a poor, but risky approach to rat control," the researchers write in their study, published in Frontiers in Ecology and Evolution.
The reason people think cats are controlling rats is because rats act differently when cats are around and are less likely to be seen by people. They'll spend more time hiding or will move around cautiously in the shadows, hoping to avoid a cat encounter.
Says Parsons, "Rats overestimate the risk posed by cats."