Kathy Corradi
Appearances
Freakonomics Radio
623. Can New York City Win Its War on Rats?
What we're effectively doing is making their lives more stressful and cutting off their superpower to breed. There's a whole 99-page report about how we're going to do that. Because, again, simple things are complex when we talk about the density of New York.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
For a longtime New York City, before we were known for our black bags on the curb, we were known for our steel trash cans on the curb, as made famous by Oscar the Grouch.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
So the can he sits in was ubiquitous to New York before the plastic bag.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
We're moving towards containers, which means basically a garbage can with a secure lid. These new containers are also made of plastic, but a much thicker grade than the flimsy bags. And as of November this year, 2024, there'll be different administrative code and legislation in place that 70 percent of New York City waste will be back in containers.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
An ounce of prevention is worth a pound of cure.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
We're waiting to kind of play out these pilots and see what the feedback is, what's the best technology that works. Rats do not care about jurisdiction. So we need to think about how we do this work as a whole of city approach.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
Some of our, quote, more sexy treatments, rat ice is one of them. That is dry ice. It off-gases carbon dioxide, and that asphyxiates the rats right in their burrows. We also use a technology called BurrowRx, a similar idea. It off-gases carbon monoxide. The rats asphyxiate in their burrow. And a new technology that's come out in the last couple of years is a canister of carbon dioxide.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
Same application. The difference with that is we can measure how much gas is flowing out of the tank. We can actually use that in closer proximity to buildings, which is really important in a dense city like New York.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
Most of the birth control contraceptive that's on the market for rats requires a constant feed, meaning they have to feed on it over and over again. And if we have food competition, that becomes a challenge.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
You know, we have a job to do, and I come to work every day committed to doing that. The immense responsibility to do this well for the city that I love, for all the people who live in this city and feel such a heavy impact from it, that's the focus.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
No, I'm just focusing on serving the public. I was out twice this week, once in Brooklyn, once in downtown Manhattan, walking with groups talking about rats. I've held folks' hands as they're tearing up about rats that are in their homes. And then on the other side, you know, folks who are inventing their own devices to keep rats out of their property. That's what I love. I love the city.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
I love our ingenuity, our human ingenuity and our rat ingenuity. And that's what keeps me fired up about this work.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
Yes, their fecundity is their superpower. Rats' gestation period is about 21 days. You know, three weeks to a litter, you can have 8 to 12 pups in that litter, and then the females in that litter are ready to breed at about three months of age again. So we just are talking exponential growth. And that's by design evolutionary.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
They want to produce as much young as possible because they're a prey species. The average life expectancy of a New York City rat, a wild rat, as we call it, is eight to 12 months. If you take that same species in the laboratory setting, it's about three years. It's a tough life out there in the wild. So the more offspring you produce, the better chance you have of passing those genes on.
Freakonomics Radio
623. Can New York City Win Its War on Rats?
We've put together this summit to bring together the leading academic minds in this space, the researchers studying urban rats, and then different municipal leaders. So we have folks joining us from Boston, D.C., Seattle. Everyone's grappling with this. No city is like, you know what? We're okay with what's going on.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
There's an economic impact as well. So thinking about damages to property. They like to chew wires, don't they? They like to chew everything. That is New York City rat czar Kathy Karate. That is literally their nature to chew. They chew through holes in foundations. They can damage different food sources.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
You know, when we're thinking about storage of food and grains and things of that nature, there's, you know, a human cost in terms of public health and then mental well-being. The mental effects on folks living in and around rats, that's well documented and being studied even more. You know, stress, anxiety, depression, documented, peer-reviewed papers saying this is real.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
There's also a public health risk. Leptospirosis is one of the more famous illnesses associated with rats, and that's due to a bacteria that they can transmit through their urine. So there's real public health concerns.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
No, I'm with you. It's certainly not the highest public health risk we have across our city or the globe.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
I was certainly taken aback. I mean, the job posting itself got a lot of fanfare.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
Yes, dogs have a vaccine for leptospirosis. There's other, I'd say, unrealized potential public health risks when it comes to rats.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
So a paper out of Columbia University studied rats across New York City and looked at the different lice, ticks, fleas they carried and also looked at different viruses, pathogens that were existing on their bodies and found a bunch of novel viruses that were living on them. There's always this threat when we're talking about viruses, about their potential to mutate and jump host.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
Because rats are so close to us in where and how they live, that threat just gets higher and higher.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
I guess. Those are not words I'd necessarily include in my 150 characters.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
I'm the citywide director of verdant mitigation for the city of New York, also known as the Rat Czar.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
Yeah, it's good. My take is the more people are talking about this topic, the better it is for the work we're doing.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
Whenever I do calls at home, my dog thinks it's an opportunity to voice his opinion as well.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
Rat mitigation is complicated. It's looking at the forest and the trees at the same time. That, again, is New York City's rat czar, Kathy Karate. Really, when it comes down to rats, what we're talking about is an animal that lives in such close proximity to humans. And that's why we have such a focus on them.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
It is true. I grew up in a house that was abutting railroad tracks. And what you need to know about rats, you'll get a quick and dirty here, is they need a place to live and they need food to eat. So any space that's not getting ongoing maintenance and can have overgrown brush or weeds, things of that nature, provides ideal habitat for them to burrow and create their nest.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
And that's what we had behind my house. With the encouragement of my mom and our neighbor, we circulated a petition to get the local train company to take care of that harborage condition and dress the rats. Did it work? It did. Yeah. You know, they cleaned the area. But the hard thing about rats is one time doesn't solve. That's why it makes it such a challenging issue.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
How I got tuned into rat mitigation work was through that role. We ran zero waste programming. And because garbage and rats go hand in hand, my team was tasked with rat mitigation on the waste side for public schools. So I was out in about 120 different school buildings talking with facility staff. How do we manage our waste better? Talking with
Freakonomics Radio
622. Why Does Everyone Hate Rats?
staff students in principle about waste sorting behaviors and how we can make cleaner waste streams, less access to food sources for rats. The key to pest management, any pest management, first and foremost is sanitation.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
There's no census. So if anyone is telling you a number, don't believe it.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
We're not going to discuss a number. It's kind of futile. And then anything you put out there then gets used as this watermark of... It was 3 million in 2024. Someone else said it was 8 million in 2006. It's an unfair assessment.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
Squirrels, chipmunks, mice, all other rodents in the city. The main focus is on rats. There's more of a community aspect when it comes to rats. They're commensal, meaning they sit at the table with us. What is that word you used, commensal? Yes, commensal. What does that mean?
Freakonomics Radio
622. Why Does Everyone Hate Rats?
It literally means like a seat at the table, meaning that they are thriving and existing because of the plate we've set for them in our urban spaces. Certainly the house mouse in a lot of regards is more successful, we can say, than a rat in terms of how it breeds and how it occupies urban spaces and non-urban spaces.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
But rats are known for their ability to exploit and thrive where humans are densest.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
In a way, and I would say people are unintentionally feeding rats all the time across our city. Maybe they're not throwing acorns or peanuts, but almost all of human behaviors in urban spaces end up feeding rats. How smart are rats? They are smart. I've not seen anything like a comparative IQ test for them.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
I would say, you know, in terms of how we gauge savviness, the rat is right up there. There's more and more research coming out about them and empathy and laughing and altruism. Seriously? Yeah. And what we know is in terms of adaptability to survive, there's few species greater. They will avoid new things in their environment because they're unsure if they're harmful or helpful.
Freakonomics Radio
622. Why Does Everyone Hate Rats?
There are stories of less dominant rats being sent out to test a new food source and then being monitored to see if there's ill effects. So they are survivors. And I would say no one except humans exploits an urban space better.