I went to rat school in New York City to see if Toronto had any hope of beating back its rodent invasion. Here’s what I learned

“If you don’t know why there’s a rat on the screen,” Corrigan said, “you’re in the wrong place.”

This was his way of welcoming 28 new students to Rat Academy, a city-run training program that he calls “rodent bootcamp.” 

Corrigan, a trim, balding man with a Brooklyn accent, frameless spectacles and a wry smile, has been the school’s lead instructor since it launched in 2005.

Rat Academy is a school for pest management professionals, public health workers and the vermin-curious. Formally called Rodent Academy, the program covers mice, too, but focuses on the pest that lives large in our cities and our nightmares: the urban rat. This year’s agenda includes a Rat Safari, a presentation on “The Secret Lives of Rodents” and a visit from New York’s infamous “Rat Czar.” 

The students are scattered throughout the room in squeaky leather chairs, each holding a dictionary-sized binder of learning materials. Among them are thick-armed pest control technicians with tales from the field; neatly dressed policy experts; health and safety managers from the world’s biggest food manufacturers; and about a dozen New York City pest management employees who work to keep rodents out of parks, restaurants and schools.

There is also me, a journalist and self-appointed ambassador for the beleaguered people of Toronto, where rodent-related property standards complaints have doubled in the past two years. I am here to learn what it will take for Canada’s rattiest city to get its alarming problem in check.

“Rodent populations globally are exploding,” Corrigan tells the class, noting that he doesn’t use that word — “exploding” — lightly. He has spent four decades studying urban rat colonies in New York and working as a pest management consultant all over the world. “Cities everywhere are saying: we’ve never had this before, the rodents are out of control.”

Why are rats thriving? There are many factors at play. Global warming has extended the rat mating season and made winters less deadly. Urban densification is producing more food waste. Ageing infrastructure means more places to burrow.

But Corrigan argues the main reason for the rat explosion is that humans are, essentially, disorganized slobs. We produce mountains of trash. We are poor planners. Faced with tough problems, our governments fail to take action until things get out of control.

Rats multiply quickly, he says. A small problem becomes a big problem. Prevention is no longer an option, and we enter crisis management mode.

We are not even 30 minutes into Rat Academy and already I feel worried. The bleak picture that Corrigan has painted — the failure to take action, the ignored warning signs — it all sounds familiar.

Toronto was supposed to create a rat mitigation strategy six years ago. In 2018, after what then-deputy mayor Ana Bailão described as a “dramatic rise” in rodent complaints across the city, council passed a motion asking staff to come up with a plan.

Residents who had been waging war against backyard rats were relieved. It seemed like the city was finally prepared to take the problem seriously.

A policy team at Municipal Licensing and Standards (MLS) spent 18 months working on a strategy, but the fall 2019 deadline passed with no report. Then COVID-19 hit, priorities changed and the rat strategy was never finished. A city spokesperson told me it was shelved due to pandemic-related resource constraints.

In rat years, that’s a long, long time. As Corrigan says, “Rats are so insidious that they are literally multiplying while we are sleeping.” A city rat lives for seven to 12 months and spends much of that time on a frantic mission to reproduce. Females have 21-day pregnancies, birthing eight to 16 pups in each litter. National Geographic calculates that it is mathematically possible for a pair of rats to produce 15,000 descendants in a single year.

Toronto’s new push to create a strategy will be our third attempt to do something about rats since 2006. That’s almost 20 years without a plan.

In the meantime, we have fallen far behind other cities that have built organized rat management programs.

New York has a city-wide rat strategy, a dedicated rodent control office and a new Rat Czar who co-ordinates mitigation efforts across 19 departments. (Job requirements: “highly motivated and somewhat bloodthirsty,” the posting said, with a “general aura of badassery.”)

Chicago provides free rat control services to residents. Vancouver is producing some of the world’s best research on urban rat populations. Even Ottawa, shaken by its own rat surge a few years ago, is doing more to prevent the spread than Toronto. The capital created a Rat Mitigation Working Group and hired a consultant — Corrigan, it turns out — to produce a rat management plan, which the councillors and staff are now acting on.

Toronto has no plan. There is no Rat Czar or working group; no single person or agency accountable for city-wide rat management. No construction bylaw. No active monitoring of the sewers. No tracking rat sightings in the parks. Responsibilities are spread among several departments — bylaw, health, sewers and parks — with no co-ordinated effort to tackle the problem.

The city isn’t actively monitoring rats through data collection. (A request for complaint figures to accompany this story took several weeks as staff retrieved and prepared the data, while Ottawa, which is actively monitoring complaints, had its own figures on hand and sent them immediately.)

Toronto is a shining example of what Corrigan would call a disorganized approach. To the unprepared, he warns: “You can pay now, or pay later.” Later will be more expensive, stressful and much harder, if not impossible.

There is a tipping point. Corrigan says that once rats “get away” from a city in numbers and spread due to inadequate proactive measures, they become very difficult and expensive to bring back to levels that residents find tolerable.

I spent a lot of time thinking about that dystopian scenario: Toronto with intolerable levels of rats.

Frustrated with Toronto’s lack of action, I had come to the Academy to write my own rat management strategy for the city, but hours in, I began to wonder whether it is even possible. Maybe the city was is already on an irreversible trajectory, doomed to be overrun.

Bobby Corrigan’s close encounters with rats started in the 1970s, when he put himself through college with a job climbing down into New York’s sewers with a bucket of poison bait. Later, as a doctoral student, he spent weekends living in a rat-infested barn in Indiana, falling asleep to mating shrieks.

“It sounds wacky but to me it was very exciting,” he tells us.

He has been known to lie on the subway floor to get “a rat’s-eye view of the place.” He once stood in the dark in an infested garbage room to “get a feel” for the rodent activity.

“I went in, closed the door and just enjoyed the moment,” he shares, closing his eyes and taking in a relaxed breath, like someone enjoying the spa.

Corrigan wears the neat and practical attire of a scientist whose job requires dirty work: trousers with hiking boots. A cellphone and watch clipped to his belt. A lanyard with his health department ID.

He has been a rodentologist for 32 years. His work, and experience living in New York, have given him a front seat to the consequences of letting rats spiral out of control.

I first met Corrigan in 2019, while reporting on the rat strategy that would never come to be, and I have since come to think of him as a sort of evidence-based Ghost of Christmas future — Critter-mas? — warning cities to heed his message, or bear the burden of rats for eternity.

Corrigan worked in private pest control in the 1970s, then spent 16 years teaching rodentology to university students before taking a job with the New York Health Department.

New York City’s rat problem has been three centuries in the making, Corrigan explains. The Norway rat, also known as the brown rat, landed in North America in the 1730s. Scientists believe it originated in Mongolia or northern China, spread to Europe during the Middle Ages, helping fuel the bubonic plague, then skittered onto ships destined for New York and other eastern ports.

Today, rats are everywhere. They are in New York’s parks, sewers, sidewalks, alleyways, subways; they are in derelict buildings; in apartment walls; in restaurant kitchens; they slip under door gaps and through nickel-sized cracks in building facades; they fall out of restaurant ceilings; one famously dragged a slice of pepperoni and cheese into a subway station, earning infamy as “Pizza Rat.”

New York’s rat explosion can be traced to the adoption of plastic garbage bags in the late 1960s and the city’s disturbing tradition of leaving mountains of trash on sidewalks, creating a buffet that has helped them burrow into every borough. Rats are now so well established in New York that eradication is impossible, Corrigan says. The best the city can do is manage the problem, an effort that costs millions of dollars each year.

“If New York City was doing good rat control 50 years ago, we would never be in this mess that we’re in,” Corrigan says.

In Toronto, rats outside food service settings are viewed as a nuisance rather than a public health concern, a position that may surprise people familiar with rodent ecology.

Rats can spread disease and infection to humans, including salmonella, rat-bite fever and leptospirosis, a bacterial pathogen transmitted in rat urine that killed six New Yorkers between 2001 and 2023. Researchers in Vancouver discovered that rats can also carry human-associated pathogens such as MRSA, the antibiotic-resistant superbug, and C. difficile, a spore-forming bacterium known to cause serious gastrointestinal disease.

Earlier this year, New York’s health department issued an advisory about an alarming uptick in cases of human leptospirosis, from an average of three cases a year in the 2000s, to 15 cases a year in the 2010s, to 24 infections last year and six in the first quarter of 2024.

Rats are also incredibly destructive. They gnaw at electrical wires and start house fires. They chew through compost bins, cause power outages and tunnel into buildings, damaging infrastructure.

Kaylee Byers, an assistant professor in the faculty of health sciences at Simon Fraser University, spent years studying the disease ecology of rats at the Vancouver Rat Project. Byers said it’s important to consider the mental health impact rats have on the people forced to live with them, rather than focusing solely on the potential for disease transmission.

In a 2019 study that examined the impact living with rats had on people in Vancouver’s Downtown Eastside, Byers and her colleagues found significant mental health consequences, including feelings of fear, anxiety, hopelessness and helplessness. For those individuals, “a lack of action from those deemed responsible represents social injustice,” Byers said.

For some, especially seniors and people living on low incomes, rat management can be prohibitively expensive. It can also feel futile. What’s the point of spending hundreds or thousands of dollars a year — even if you can afford it — for a pest control technician to lay bait stations on your property when no one is addressing the root of the problem, the dumpster down the street or the dilapidated shed next door? Bylaw officers can inspect problem properties, but only if residents know where the rats are coming from and choose to report their neighbours.

I ask Corrigan for his take on Toronto’s argument that rats aren’t a public health threat unless they are connected to food premises. It is true, he allows, that while rats carry many pathogens, they don’t often transmit them to humans.

“I always say they’re a potential public health threat,” Corrigan says. It’s a view shared by the U.S. Centers for Disease Control.

“Some cities, because people are not dying, they see it more as a nuisance,” Corrigan says. “But here’s the problem. How long are we going to push the envelope before a virus that is very compatible with that species and very viral to us comes together?”

In Corrigan’s view, forward-thinking, progressive and environmentally responsible cities must try to attain as close to a “rat-free” city as possible.

Rats may not be killing people in large numbers in North America, “but where was COVID for a million years?”

My time at Rat Academy passed quickly.

I met the Rat Czar, Kathleen Corradi, who is warm and thoughtful, not quite what one would expect from the “bloodthirsty” job description, and who stressed the importance of having a plan. “Rats are urban exploiters,” she said. “Any inch we miss is an inch they’re going to take.”

I learned about “The Secret Lives of Rodents” from B.C. entomologist Kurtis Brown, who showed us a photograph of a mouse-built “urine castle” — a stalagmite of pee, sebum, fur and secretions — and said, with a sigh of pleasure, “I get really, really excited when I see stuff like this.” (Rodents communicate through these deposits, which he finds fascinating. “This is mouse Tinder,” he says. “I mean, it’s analog, but it’s pretty cool.”)

I spent my final day on a Rat Safari, crawling around in infested alleyways, parks and subway stations to examine droppings (fresh is dark; old is dusty) and search for other ARS: Active Rodent Signs. On my own time, I saw rats everywhere: darting out from under a food stall in Brooklyn, running along the subway tracks at Penn Station, slipping into a sidewalk hole in the financial district. I stop counting after 23.

At home a few weeks later, I received mail from the city of New York, a large manila envelope with a rat sticker on the front. Inside was a graduation certificate. I was, officially, a Rat Detective.

You can read my recommendations in Part 2 of the series.

A few weeks ago in Toronto, a rat was spotted in the seating area of an upscale coffee roastery downtown. TikTokers compared it to the rodent chef from “Ratatouille.” “Leave remy alone, he makes great coffee,” one wrote. Most people laughed, but I was haunted by its boldness. It seemed to have the swagger of a New York rat.

While reporting this story, I heard from a homeowner in the Junction Triangle who discovered an extensive rat nest under an addition at the back of her house. “It was a warren of tunnels that, for lack of a better word, looked professional,” she said. “They have complete control.” A Corso Italia resident told me about a dead rat on her street that was “left to bake in the sun and has since fused into the sidewalk and become one with the concrete.”

I went to Rat Academy thinking that my reporting would make me fear for Toronto and give me relentless nightmares — and it did — but what I discovered in New York, aside from two dozen rats, trash bags quaking with rodent movements, and infestations older than America itself, was a surprisingly hopeful story.

The rat situation in Toronto isn’t a lost cause. At least not yet. Even New York, a city with — there’s no other way to put it — intolerable levels of rats, has somehow held onto hope. 

Toronto has a choice. We can be a city that gets ahead of the problem, keeps rat populations at manageable levels, maintains quality of life, protects infrastructure and keeps spending in control.

Or we can leave it on the backburner and wait for rats to take over.