NYC Rats vs. Alleycats: the Battle to Improve Public Health

City hall announced a $2.9 million campaign against the city’s vermin last month, an increase of over $2 million from last year, as a sign that Mayor de Blasio is going all in on a new strategy to eradicate Gotham’s squeakiest pests. 

The multimillion-dollar campaign boasts a more scientific approach to rat control, using animal population data to locate problem areas for health inspectors to bait with poisons, but the city’s umbrella group for animal welfare wants to deploy a more natural predator against the city’s brown rats—feral cats.

There are millions of rats in New York City, though experts say there’s no reliable way to count them all. Or to get rid of them. Rats multiply exponentially, feed on garbage and carry diseases. The U.S. Centers for Disease Control and Prevention warn that rats can spread viruses and bacteria through bodily fluids or the mites and fleas living in their fur. A rat's gnawing teeth can cut through walls, wires, bone and even steel. They are smart, resilient and they have lived here for 400 years—wreaking havoc on the city’s infrastructure, housing and humans.

Senior health officials said the increase in funds was necessary to implement their new strategy to combat these rodents since they pose a health risk to New York’s human population, especially its most vulnerable groups. 

“Low-income communities in New York City have far greater rates of interior pest and rodent infestation primarily because of the connection to poor housing conditions,”Dr. Mary Bassett, commissioner of the city’s department of health and mental hygiene said. “It is crucial that pests be controlled safely, and that pesticides are used judiciously.”

Rat poison plays a major role in the plan. But that isn’t new. What is new is a strategy the city’s senior rodentologist calls a “scientific approach of attacking rat reservoirs.”

Health officials say rats nest in underground lairs beneath plants and shrubs in city parks, despite previous attempts to poison them. Under the plan, inspectors will make daytime and nighttime inspections to track the rats back to their burrows where bait can be laid out on their doorstep.

The health department trumpets a 90 percent success rate in neighborhoods that were tested under at $611,000 trial run of the strategy last year, and are confident that expanding this “integrated pest management”plan citywide will have similar results.

But, as The New York Times pointed out, there have been 109 mayors in the history of the city and nearly as many anti-rat plans. “Their collective record is approximately 0-108.”

Other groups are similarly skeptical and offer alternative solutions.

One organization currently not receiving any funding to fight rats is the Mayor’s Alliance for NYC’s Animals. While the non-governmental, nonprofit umbrella group is not opposed to killing the city’s rats—as their name might suggest—it advocates a more traditional strategy that appears to be gaining traction across the country: using alley cats to kill the rats.

"There was a reason the ancient Egyptians had cats in a granary,”said Jane Hoffman, president of the alliance. “They kill vermin.”

One of Hoffman’s projects is called the Feral Cat Initiative, which aims to trap, vaccinate, neuter and return street cats to a colony with other felines. Free from the distractions of having to find food, shelter or water—which are provided by a colony caretaker—the cats prey on rats and a other pests which might lurk around benches, bushes and garbage bins.

"They'll kill rats, they'll kill mice, they'll kill cockroaches. And,”she paused, “they might kill pigeons.”

The Mayor’s Alliance for Animals is not the only organization preaching the virtues of feral cats.

Disneyland, in California, has maintained a 200-cat colony to keep rodents under control in the theme park for years. The Los Angeles Police Department has several precincts that use feral cats to control rodents sneaking around their storehouses. And in Chicago, the local humane society can’t keep up with demands from locals to host new feral cat colonies to control their rat problems.

“There's a waiting list for feral cats in the city of Chicago,” said Anne Beall, a research marketing executive and a convert to the feral cat approach to pest management. She and her husband had such bad rat problems that they considered moving out.

"We tried poison, we tried drowning them, we tried gas, we tried everything. Nothing, nothing worked,”she said. “And literally the only thing that worked was when we got the cats.”

"We don't think of cats as working animals but they can serve a function,”she said.

Beall conducted a study to estimate just how effective the cats were at killing rats. Based on observations by cat owners or those who have them on their property, she found that cats are observed killing over 17 million rats a year nationwide. That number could be 3 to 4 times higher, since cats will also kill rats that are never seen by people.

Dr. Robert Corrigan is unconvinced. As New York City’s premier urban rodentologist and long-time advisor to the city’s health department, he does not see cats as the solution to the city’s rat problem.

“It just doesn't have scientific credibility,”Corrigan said. The research that has been done by mammalogists, he said, “found that cats are not an effective control agent of city populations of rats.”

Dr. Gregory Glass, one of the researchers behind one such study, agreed. “Using cats to control [brown] rats is a waste of time,”he said.

Very little scientific research has been done on the topic. As Dr. Glass’own 2009 study points out, cats and rats are among the most studied urban animals, but the literature on the predator-prey relationship between them is “surprisingly lacking.”There are just a couple of studies that focus exclusively on the subject of the impact of feral cats on urban rat populations.

Groups like the Mayor’s Alliance for NYC Animals says that doesn’t give you the whole picture. The scent of the cats also serves to scare rats away, Hoffman says.

But that claim remains unproven, Corrigan contends. If there was science to support feral cats as effective rat catchers or deterrents, he might consider it.

"I'm a scientist on this,”Corrigan said. “I'm not opposed to it or for it. Just do some science."

More important, he said, is the issue of how the rats are being fed—the readily accessible piles of food waste on the curbs are the real problem. Some of the funding for the new plan will go to efforts to reduce the garbage, he said.

“People are totally accepting now of mountains of trash without being repulsed by that,”Corrigan said, remembering an article that called New York City the “trash-opolis”of the United States. “You know, we're the number one rat-tropolis.”He doesn’t think that's a coincidence.

Many feral cat and rat experts agree that the key to reducing rats is by improving a city’s sanitation practices: reduce the food supply and you can reduce the rats.

New York City’s sanitation department doesn’t appear to agree that the street side trash is an issue. Over the last three years, they have consistently given themselves straight A’s for street and sidewalk cleanliness in their annual self-evaluation, rating over 93 percent of streets and over 96 percent of sidewalks “acceptably clean.”Less than one half of one percent of streets or sidewalks were rated “filthy”in the same time period.

Regardless of the persistent trash problem, the cat advocates maintain that using the city’s feral felines to control pests is a practical, low-cost solution.

"We have more cats than we can find homes for,”Hoffman said. “Why don't we look at innovative ways to utilize what is essentially a resource?"