Rats are on the rise. Here’s what cities are doing about it

Where there is food, there will be rats.

Much like it shook most everything else in the world, the COVID pandemic shifted where rats went to seek out their meals. As restaurants and businesses across the country closed suddenly, rats had to adapt to find food in residential areas as people returned home en masse.

The stress of finding new food sources killed an estimated hundreds of thousands, if not millions, of rats, renowned rodentologist Bobby Corrigan said. But now that they have adapted, and restaurants and businesses have reopened, the rodents have rebounded, with populations on the rise in many major cities. Climate change has brought longer stretches of warmer weather, which means more time for breeding.

Unlike the animated rat-turned- world-class- chef made popular by a children’s film, the booming rat population has not been met with open arms. They cause billions of dollars in damage annually around the world, and carry diseases that can be harmful and sometimes deadly.

Cities have had to adapt their approach to controlling these vermin — something Corrigan said we should really view as managing a wildlife species.

Rats are, “a thing of beauty in many different ways,” Corrigan said, and “as a mammal, it’s a very successful mammal.”

“It needs a lot of attention, it needs money, it needs science. We need to follow that science as it emerges,” he said. In other words — they’re not just pests.

For eight years in a row, the pest control company Orkin has ranked Chicago as America’s “rattiest city,” based on the number of new residential and commercial rat treatments. In 2022, Orkin’s most recent list, New York City was No.2, with Los Angeles, Washington, D.C., and San Francisco rounding out the top five.

The most common rat species in the United States, the Norway rat, first came to the country around 1775, according to the Environmental Protection Agency, on ships originating from Europe. Since then, they’ve been spreading quickly, following humans and their food. They have become a critical part of the ecosystem, Corrigan said, and are intertwined with many parts of city management.

“We’re piled up on top of each other. And so as the people increase, the density increases, the refuse increases, and our cities get older and older and older, we end up with these [rat] populations that are reflecting our increases in our density,” Corrigan said.

The main culprit for the rise in rats? Trash. It’s something U.S. cities are taking action to address.

Among many rat control initiatives this year, New York City has changed trash take-out times for businesses and residents to prevent garbage from sitting out for hours on end. New York City has also started requiring all food-related businesses — some 40,000 bodegas, restaurants, delis and grocery stores — to dispose of food waste in secure containers instead of trash bags on the street.

In Washington, D.C., Mayor Muriel Bowser allocated $3.4 million for the 2024 fiscal year to begin replacing residents’ trash bins with newer and larger cans over the next eight years.

Both cities have taken other actions, too.

New York City Mayor Eric Adams has declared rats public enemy No. 1, targeting so-called rat mitigation zones in neighborhoods with historically high rat activity, for routine inspections. He hired Kathleen Corradi, a former elementary school teacher who led the city’s education department’s rodent reduction program, as the city’s first rat czar.

“I feel an intense ownership and responsibility for the over 8 million New Yorkers who have dealt with rats and unclean streets for too long,” Corradi said.

In the months following her taking on the role in May, Corradi said, “we saw about a 20% reduction in rat sightings, which tells me New Yorkers are bought in. They’re taking the steps already needed to make sure we’re going rat free in our city.”

But for Corrigan, who lives in Brooklyn, it’s too early to claim victory.

“We want to make sure that the city maintains that momentum,” he said.

In the 2022 fiscal year, the District of Columbia’s 3-1-1 hotline logged 13,300 complaints, compared to roughly 6,000 in 2018. Already this fiscal year, DC Health has received 13,000 complaints, well on pace to surpass 2022’s numbers. Gerard Brown, program manager of the Rodent and Vector Control Division for DC Health, urges residents to use a garbage disposal for food waste, wash take-out containers before discarding them and throw out food as close to garbage day as possible.

Globally, a number of countries have pushed rat eradication in recent years. New Zealand has pledged to rid itself of all rats by 2050. Alberta, Canada is one success story: Thanks to its rat control program, residents there have been living rat-free since 1950.

For all the negatives, rats do have an upside. Corrigan estimates rodents have added 25 to 30 years to humans’ longevity as a species because of their role in scientific research.

“Every drug we use has been tested on rats first — every cosmetic, every anti-cancer drug,” Corrigan said. “So to some degree, I would say to everybody: When you walk down the street, if you do see a rat, before you think about ‘how are we going to manage it?’ say, ‘by the way, thanks a lot.’”