Sept. 27 (UPI) -- It turns out, cats are overrated rat predators.
In a first-of-its-kind study, scientists tracked interactions between feral cats and local rat populations. Using microchips to track the movements of rodent populations, scientists showed rats are adept at avoiding cats.
Over the course of 79-day study, scientists recorded only two cat-caused rat deaths.
"Like any prey, rats overestimate the risks of predation. In the presence of cats, they adjust their behavior to make themselves less apparent and spend more time in burrows," lead researcher Dr. Michael H. Parsons, a visiting scholar at Fordham University, said in a news release. "This raises questions about whether releasing cats in the city to control rats is worth the risks cats pose to wildlife."
Biologists have previously argued cats prefer to prey on smaller, defenseless animals, like birds and native mammals, like voles and shrews.
"New Yorkers often boast their rats 'aren't afraid of anything' and are the 'size of a cat'," said Parsons. "Yet cats are commonly released to control this relatively large, defensive and potentially dangerous prey."
Parsons and his colleagues were already studying rat populations at a New York City waste recycling center when a group of feral cats moved into the area, offering the researchers a unique opportunity to observe feline-rodent interactions.
Microchips and motion-sensor cameras helped researchers track the effects of the cats on the rats' behavior.
Because the rats were so large and effective at hiding, researchers expected a low rate of predation. Their findings -- published this week in the journal Frontiers in Ecology and Evolution -- confirmed their hypothesis.
The new research suggests the presence of cats doesn't actually shrink local rat populations, but may make them less visible.
"People see fewer rats and assume it's because the cats have killed them -- whereas it's actually due to the rats changing their behavior," said Parsons. "The results of our study suggest the benefits of releasing cats are far outweighed by the risks to wildlife."