622. Why Does Everyone Hate Rats?

Summary

Podcast Summary: Freakonomics Radio Episode 622 – "Why Does Everyone Hate Rats?"

Release Date: February 14, 2025
Host: Stephen J. Dubner
Title: Freakonomics Radio
Episode Title: Why Does Everyone Hate Rats?
Duration: Approximately 45 minutes
Transcript Coverage: [00:00] – [45:22]

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Introduction to the "Rat Problem" in New York City

The episode opens with a provocative exploration of the pervasive dislike for rats, particularly in urban environments like New York City. Stephen Dubner introduces the central theme by highlighting a controversial job listing posted by New York City's Mayor, Eric Adams, aimed at hiring an individual dedicated to rat mitigation. Dubner points out the depth of Adams's resentment towards rats, framing them as "Public enemy number one" and emphasizing the mayor's unwavering commitment to combating them despite his legal troubles.

Notable Quote:

Stephen Dubner [00:45]: "Rats do something to traumatize you. And I hate rats. That is Eric Adams, the mayor of New York City."

Interview with Kathy Karate: NYC’s Rat Czar

Dubner interviews Kathy Karate, the Director of Rodent Mitigation for New York City, affectionately known as the "Rat Czar." She delves into her personal history with rats, tracing her early experiences growing up adjacent to railroad tracks where rat infestation was a persistent issue. Her professional journey from biology and urban sustainability to her current role illustrates the complexities of managing rat populations in one of the world's most densely populated cities.

Key Points:

• Rat Biology and Behavior: Rats thrive in urban settings due to their close proximity to human activities, making sanitation the cornerstone of effective pest management.
• Challenges in Rat Mitigation: One-time efforts, like cleaning harborage areas, offer temporary relief as rat populations quickly rebound, necessitating ongoing and comprehensive strategies.
• Impact on Public Health and Mental Well-being: Rats contribute to infrastructure damage (e.g., chewing through wires) and pose health risks through diseases like leptospirosis, though such incidents are relatively rare in large populations.

Notable Quotes:

Kathy Karate [07:36]: "It is true. I grew up in a house that was abutting railroad tracks. And what you need to know about rats... they need a place to live and they need food to eat."

Kathy Karate [08:27]: "Most people, when they think about sanitation, generally do not think of New York City. But trash on the sidewalks represents paradise for rats."

Historical Context: Rats and the Black Death

The conversation shifts to the historical association between rats and the spread of the bubonic plague, famously known as the Black Death. Science journalist Bethany Brookshire provides a nuanced view, challenging the long-held belief that rats were the primary vectors of this devastating pandemic.

Key Points:

• Plague Transmission Misconceptions: Brookshire explains that the traditional view attributing the Black Death to rats and their fleas lacks substantial historical and archaeological evidence.
• Alternative Transmission Models: Professor Nils Christian Stenseth introduces the idea that human ectoparasites (like body lice and human fleas) were more likely responsible for the rapid spread of the plague, aligning better with historical mortality rates and the speed of dissemination.

Notable Quotes:

Bethany Brookshire [12:29]: "We really hate them. We hate their success because their success feels like our failure."

Nils Christian Stenseth [16:07]: "And in 2018, Stenseth and his colleagues published a paper... they presented a different model."

Nils Christian Stenseth [22:02]: "It became very clear that rat could not have played a major role in the spread of plague in Europe."

Economic Perspectives: Insights from Ed Glazer

Ed Glazer, an economist from Harvard University, discusses the economic implications of rat populations in urban settings. He contextualizes rats as agents of negative externalities, contributing to public health risks and infrastructure damage while questioning any potential positive impacts.

Key Points:

• Economic Externalities: Rats impose costs on cities through property damage and health risks, necessitating public expenditure on mitigation efforts.
• Urban Success and Rat Proliferation: Glazer observes that successful urban environments inadvertently support thriving rat populations, which in turn can amplify public health and economic challenges.
• Post-Pandemic Rat Surge: The surge in rat populations post-COVID-19 is attributed to diminished city services and increased food availability from outdoor dining setups.

Notable Quotes:

Ed Glazer [22:27]: "Blaming the rat is pretty much, you know, game over in terms of the rat's global reputation."

Ed Glazer [24:51]: "Rats are... they're agents of usually negative externalities within cities."

Cultural Perceptions: Beyond Western Views

Bethany Brookshire elaborates on the diverse cultural perceptions of rats, contrasting Western disdain with reverence in other societies. She highlights the Temple of Karni Mata in India, where rats are considered sacred and are revered rather than vilified.

Key Points:

• Subjectivity of Animal Villainy: The classification of animals as pests is largely subjective and influenced by cultural contexts rather than inherent traits of the animals themselves.
• Sacred Rats: In Deshnoge, India, approximately 25,000 black rats are worshipped as reincarnations of humans, receiving care and reverence from devotees.
• Historical Shifts in Perception: Brookshire discusses how societal roles and necessities dictate the status of animals, using pigeons as an example of species whose reputations have declined as their practical uses faded.

Notable Quotes:

Bethany Brookshire [31:42]: "I'm the author of the 2022 book How Humans Create Animal Villains."

Bethany Brookshire [37:23]: "The fact that we're so quick to blame the rat says a lot about us."

Economic and Urban Policy Recommendations

Kathy Karate emphasizes the importance of effective waste management as a critical factor in controlling rat populations. She argues that consistent and thorough sanitation efforts can significantly reduce the availability of food sources for rats, thereby mitigating their proliferation.

Key Points:

• Waste Management: Removing trash bags from streets is identified as the single most effective measure in reducing rat populations.
• Public Health Policies: While acknowledging that leptospirosis cases are relatively low, Karate underscores the potential for emerging public health risks due to rats carrying novel viruses.

Notable Quotes:

Kathy Karate [44:45]: "I believe that the single biggest swing that you can take at the rat problem in New York City is getting the trash bags off of the streets."

Conclusion and Future Directions

Dubner wraps up the episode by teasing a second part of the series, promising to delve deeper into strategies for managing rat populations and exploring successful rat-free environments. The episode underscores the multifaceted nature of human-rat interactions, intertwining historical misconceptions, economic impacts, and cultural narratives.

Notable Quotes:

Stephen Dubner [43:46]: "Could I interest you in Sympathy for the Rat?"

Ed Glazer [44:45]: "Sympathy for a creature that, you know, coexisted with us... seems like it makes more sense."

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Key Takeaways:

1. Complex Relationship: The human relationship with rats is intricate, influenced by historical events, economic factors, and cultural perceptions.
2. Misattributed Blame: Traditional beliefs about rats as primary vectors of the Black Death are being reexamined, with potential alternative explanations gaining traction.
3. Urban Challenges: Effective rat mitigation requires comprehensive strategies focused on sanitation and waste management, highlighting the broader challenges of maintaining urban hygiene.
4. Cultural Relativity: The perception of rats varies globally, demonstrating that societal values and cultural narratives significantly shape how animals are viewed and treated.
5. Economic Implications: Rats represent negative externalities in urban economies, necessitating public policies that balance control measures with humane treatment.

Notable Moments and Quotes with Timestamps:

• [00:45] Stephen Dubner: "Rats do something to traumatize you. And I hate rats. That is Eric Adams, the mayor of New York City."

• [07:36] Kathy Karate: "I grew up in a house that was abutting railroad tracks... they need a place to live and they need food to eat."

• [12:29] Bethany Brookshire: "We really hate them. We hate their success because their success feels like our failure."

• [16:07] Nils Christian Stenseth: "In 2018, Stenseth and his colleagues published a paper... they presented a different model."

• [22:27] Ed Glazer: "Blaming the rat is pretty much... game over in terms of the rat's global reputation."

• [31:42] Bethany Brookshire: "I'm the author of the 2022 book How Humans Create Animal Villains."

• [37:23] Bethany Brookshire: "The fact that we're so quick to blame the rat says a lot about us."

• [44:45] Kathy Karate: "I believe that the single biggest swing that you can take at the rat problem in New York City is getting the trash bags off of the streets."

• [43:46] Stephen Dubner: "Could I interest you in Sympathy for the Rat?"

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Final Thoughts

Episode 622 of Freakonomics Radio offers a comprehensive exploration of the ubiquitous disdain for rats, dissecting it through historical, economic, and cultural lenses. By engaging with experts like Kathy Karate, Bethany Brookshire, and Ed Glazer, Dubner provides listeners with a multifaceted understanding of why rats are so vilified and what can be done to manage their populations effectively in urban environments. The episode challenges preconceived notions and encourages a more empathetic and informed approach to dealing with one of humanity's oldest adversaries.

Transcript

[Stephen Dubner]

Freeconomics Radio is sponsored by Discover. It's smart to always have a few financial goals and a really smart one you can set earning cash back on what you buy every day. And with Discover you can get this Discover automatically matches all the cash back you've earned at the end of your first year. Seriously, all of it. And we trust you to make smart decisions. After all, you listen to this show see [e-mail] Credit Card Freakonomics Radio is sponsored by Mint Mobile with plans as low as 15 bucks a month. All plans come with high speed data and unlimited talk and text delivered on the nation's largest 5G network. Shop [e-mail] freak upfront payment of $45 for 3 month 5 gigabyte plan required equivalent to $15 a month new customer offer for first 3 months only, then full price plan options, taxes and fees extra. See Mint Mobile for details. Hey there Stephen Dubner. This year will mark a pair of anniversaries for us, and even though I ignore most anniversaries, these two have got their hooks in me. It has been 20 years since Steve Levitt and I published Freakonomics and it's been 15 years since I started Freakonomics Radio. So we are thinking about making some kind anniversary episode and I want to know if you have anything to share. Maybe it's a story about how you were influenced or inspired by something from Freakonomics. Maybe it's some kind of memory or coincidence that you'd like to tell us about. Whatever it is, send us an email or a voice memo, whichever you prefer. Our address is radioreconomics.com thanks in advance for that. And as always, thanks for listening. In the fall of 2022, a new job listing was posted on a New York City government website. The ideal candidate, the listing read, is highly motivated and somewhat bloodthirsty, determined to look at all solutions from various angles, including data collection, technology innovation and wholesale slaughter. And what kind of government job requires wholesale slaughter? Here is the man responsible for this listing. Rats do something to traumatize you. And I hate rats. That is Eric Adams, the mayor of New York City. If you walk down the block and a rat runs across your foot, you never forget it. Every time you walk down that block, you relive that. As you may have heard, Adams was indicted last year on five federal criminal charges, including bribery and wire fraud, although in a remarkable departure from legal precedent, the Trump administration Justice Department just ordered those charges dismissed. Through it all, the mayor's anti rat fervor has been Undiminished. Fighting crime, fighting inequality, fighting rats. Public enemy number one, many of you don't know are rats. If you're not scared of rats, you are really my hero. And that job that was posted on NYC.gov that was Eric Adams searching for his hero who turned out to be this person.

[Kathy Karate]

I was certainly taken aback. I mean, the job posting itself got a lot of fanfare.

[Stephen Dubner]

I just want to read it to you verbatim. The job posting called for someone with a quote, swashbuckling attitude, crafty humor, and a general aura of badassery.

[Kathy Karate]

Yeah.

[Stephen Dubner]

Is that you?

[Kathy Karate]

I guess. Those are not words I'd necessarily include in my 150 characters, but come on.

[Stephen Dubner]

It sounds like you fit pretty well.

[Kathy Karate]

Yeah, thank you.

[Stephen Dubner]

And that swashbuckling badass is Kathy Karate.

[Kathy Karate]

I'm the citywide director of Rodent mitigation for the city of New York, also known as the Rat Czar.

[Stephen Dubner]

And how do you like that title, the Rat Czar?

[Kathy Karate]

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.

[Stephen Dubner]

New York and many other cities have seen a rise in their rat populations, especially during COVID and now they are fighting. But is wholesale slaughter really the way to go? That is one of the many rat questions that I am eager to answer over the next few episodes. The brown rat, also known as Rattus norvegicus, is one of the most reviled animals in the world.

[Bethany Brookshire]

We really hate them. We hate their success because their success feels like are failure.

[Stephen Dubner]

We will hear the details of New York's rat mitigation plan.

[Kathy Karate]

There's a whole 99 page report about how we're going to do that.

[Stephen Dubner]

But we will also hear from rat lovers eventually.

[Bethany Brookshire]

Because you're feeding it, because it's a.

[Kathy Karate]

Little bit lovely, you end up feeling.

[Stephen Dubner]

Some warmth towards it and what you might call rat exonerators.

[Ed Glazer]

Blaming the rat is pretty much, you know, game over in terms of the rat's global reputation.

[Stephen Dubner]

And let's not forget the rat as cultural icon. This is a story about a rat.

[Kathy Karate]

Who wants to become a chef.

[Ed Glazer]

Everyone laughs, everyone gets it. You're sold.

[Stephen Dubner]

Are you sold? I'm gonna take that as a yes. Our three part series on rats begins now.

[Bethany Brookshire]

This is Freakonomics Radio, the podcast that explores the hidden side of everything with your host, Stephen Dubner.

[Kathy Karate]

Rat mitigation is complicated. It's looking at the forest and the trees at the same time.

[Stephen Dubner]

That again, is New York City's Rat Czar.

[Kathy Karate]

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.

[Stephen Dubner]

I understand that your relationship with rats goes back pretty far to when you were a kid growing up in New York. I understand that you circulated a petition in your neighborhood to get rid of some rats. Is that true?

[Kathy Karate]

It is true. I grew up in a house that was abutting railroad tracks. And what you need to know about rats, and 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. 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.

[Stephen Dubner]

Did it work?

[Kathy Karate]

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.

[Stephen Dubner]

Karate wound up getting an undergraduate degree in biology and a master's in urban sustainability. She taught elementary school for a while, and then she took a job in New York City's Department of Education in their sustainability office.

[Kathy Karate]

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 and about to 120 different school buildings, talking with facility staff, how do we manage our waste better? Talking with staff, students in principal 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.

[Stephen Dubner]

Most people, when they think about sanitation, generally do not think of New York City. There are many things to love about this place, many things worth admiring. But let's be honest, it is not a particularly clean city. Trash on the sidewalks is a thing, especially food wrappers and big bags of restaurant trash. For a population of rats, all that food waste represents something like paradise. And how big is New York's rat population?

[Kathy Karate]

There's no census, so if anyone is telling you a number, don't believe it.

[Stephen Dubner]

I have seen an estimate by M and M pest control that puts the city's rat population at around 3 million. Do you think that's Ballpark or no chance.

[Kathy Karate]

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.

[Stephen Dubner]

Now let me go back to your official title, Director of Rodent mitigation. Does that include squirrels, chipmunks, et cetera?

[Kathy Karate]

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 ra. They're commensal, meaning they sit at the table with us.

[Stephen Dubner]

What is that word you used? Commensal?

[Kathy Karate]

Yes, commensal.

[Stephen Dubner]

What does that mean?

[Kathy Karate]

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. But rats are known for their ability to exploit and thrive where humans are densest.

[Stephen Dubner]

How do you think about rats versus the other rodents that are sometimes a problem? Rats look like bigger mice, sort of. And then there are squirrels, which most people seem to think are really cute. And people feed squirrels outside. I've never seen anybody feeding a rat outside. But is a rat just a squirrel with less attractive body hair?

[Kathy Karate]

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.

[Stephen Dubner]

How smart are rats?

[Kathy Karate]

They are smart. I have not seen anything like a comparative IQ test for them.

[Stephen Dubner]

I mean, chipmunks always look pretty dumb to me. They're super cute, but they look dumb. Maybe I'm wrong.

[Kathy Karate]

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.

[Stephen Dubner]

Seriously?

[Kathy Karate]

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. 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 effect. They are survivors. And I would say no one except humans exploits an urban space better.

[Stephen Dubner]

Rats have been exploiting New York City's urban space for at least a few hundred years. The ancestors of today's rats are thought to have arrived in the 18th century on ships from Europe. But in the historical rat timeline, that is still relatively recent. Genetically, they date back to the time of dinosaurs. Today, there are two main species. The black rat, Radus rattus, which likely originated in India, and then the brown rat that we are familiar with, Radus nervegicus, the Norway rat, even though it did not originate in Norway. So why is it called that?

[Bethany Brookshire]

Because everybody who hates rats wants to name them after somebody they don't like.

[Stephen Dubner]

That is Bethany Brookshire.

[Bethany Brookshire]

So basically the name stuck because somebody was picking a fight with Norway at the time.

[Stephen Dubner]

Brookshire is a science journalist with a PhD in physiology and pharmacology. She recently published a book called How Humans Create Animal Villains. So you can see where her allegiance lies. Here is some more rat history.

[Bethany Brookshire]

Europe was very black rat dominated until we think the 17th or 18th centuries, when we began to see the brown rat that is native to what we think of as Mongolia, Rattus norvegicus ended up getting spread into Europe. And then with colonialism, it just went everywhere else, because rats and boats go together real good. Interestingly, people have not liked rats, but they didn't necessarily consider them disgusting until about the 18th or 19th century. People didn't like them because they were a problem of the food supply. Right? They would get in and they would eat your food. Nobody wants that. But they weren't considered to be disgusting in terms of. They weren't considered to carry disease for a very long time. The association of rats with disease is a relatively recent one.

[Stephen Dubner]

How did that association come to be made, and how much does it intersect with the plague in Europe?

[Bethany Brookshire]

It intersects with the plague, but not when you think it does. So there have been three major pandemics of plague that we know of in recorded history. The first was the plague of Justinian, which I believe was in the 6th century. The second was the Black Death, which was famous and began in the 14th century. The third global pandemic of bubonic plague is now. It began in the 19th century, but it persists even now. Actually, people every year in the United States, in Mongolia, and in Madagascar in particular, get plague.

[Stephen Dubner]

To be clear, the plague persists today in very small numbers, just a few hundred reported cases a year, fewer than a dozen in the U.S. but this third wave of bubonic plague has done terrible damage over the past hundred years. In India, especially during the early 20th century, and in Vietnam, during its war in the 1960s and 70s. The plague is caused by a bacterium.

[Bethany Brookshire]

Known as Yersinia pestis.

[Stephen Dubner]

You see, it's right there in the name Yersinia pestis. The Yersinia part comes from Alexandre Yersin, the first scientist to describe and culture these bacteria.

[Bethany Brookshire]

The bubonic plague is technically not a disease of humans. It is a disease of rats and fleas that happens to spill over into humans from time to time with catastrophic effects.

[Stephen Dubner]

And how much do we know about how the plague is spread?

[Bethany Brookshire]

What we do know is that fleas get Yersinia pestis, and then the bacteria forms a biofilm inside the esophagus of the rat flea, and the biofilm coats the esophagus so that the rat flea can't swallow. It's just biting and biting and biting and biting, but it can't swallow anything and it starves to death. And you start to feel really bad for the flea until you realize that everything it bites, it's barfing up little bits of bacteria into the bite, spreading plague. So that's how plague is traditionally transmitted.

[Stephen Dubner]

Okay, and then how is plague spread between humans? For that, we will bring in another scientist.

[Nils Christian Stenseth]

In humans, it can be spread partly by ectoparasites or by droplets. So coughing when you're having a cold, then that's a way of transmission.

[Stephen Dubner]

That is Nils Christian Stenseth, a professor of ecology and evolution at the University of Oslo.

[Nils Christian Stenseth]

And for the last 25 years or so, I've been studying plague. Yersenia pestis, the bacterium that caused the Black Death.

[Stephen Dubner]

The Black Death tore through Europe in the mid14th century. It is hard to believe just how brutal it was.

[Nils Christian Stenseth]

The Black Death killed half of the European population in a year or two. The plague expresses itself in the human being in three different forms. The most common one is bubonic, where it's swellings on the body that may evolve into a pneumonomic one that goes into the lung, and both might develop into a form that goes into the blood. If you're infected by eosinopestis, if you don't come to a doctor within four or five days, you can consider yourself being dead.

[Stephen Dubner]

During the Middle Ages, it was neither rats nor fleas who were thought to be responsible for the Black Death. Most of the blame was put on witches and Jews. But time and science eventually caught up with the rats. And if anything is going to give an animal species a bad reputation, it's killing off half of Europe. The association between rats and plague remains strong. Today, in the opening credits of the Decameron, a new Netflix show set during the Black Death, a massive swarm of rats come together to spell out the title. And the recent remake of the film Nosferatu shows a pack of rats following the vampire carrying the plague with them. But were rats really responsible for the Black Death?

[Nils Christian Stenseth]

That's the one that most people think are the right one. They are wrong.

[Stephen Dubner]

That's coming up after the break. I'm Stephen Dubner and this is Freakonomics Radio T Mobile 5G Home Internet keeps getting better get our fastest connection loaded with Benefits get T Mobile's best home Internet starting at 55 bucks a month without a pay in any voice line plus price lock. We won't raise your rate on Internet. Check availability@t mobile.com home Internet exclusions like taxes and fees apply. Guarantees regular monthly rate plan price of fixed wireless 5G Internet data with qualifying service after $15 bill credit with postpaid voice line plus $5 a month without auto pay with debit or bank account Regulatory fees included for qualifying accounts. $35 connection charge applies. Speeds vary due to factors affecting cellular networks. Building a portfolio with Fidelity Basket Portfolios is kind of like making a sandwich. It's as simple stocks and ETFs sort of like your meats and other topics and managing it as one big juicy investment. Now that's pretty good. Learn [e-mail] baskets Investing involves risks, including risk of loss. Fidelity Brokerage Services LLC Member NYSE SIPC.

[Kathy Karate]

My dad works in B2B marketing. He came by my school for Career day and said he was a big roas man. Then he told everyone how much he loved calculating his return on ad spend. My friends still laugh at me to this day.

[Stephen Dubner]

Not everyone gets B2B, but with LinkedIn you'll be able to reach people who do get a hundred dollar credit on your next ad campaign. Go to LinkedIn.com results to claim your credit. That's LinkedIn.com results. Terms and conditions apply. LinkedIn the place to be, to Be One reason that rats are so despised is because they spread disease, the most famous instance being the Black Death, a pandemic of bubonic plague in the 14th century that killed millions upon millions of Europeans. But scientists have recently challenged the claim that rats caused the Black Death. Scientists, including Niels Christian Stentseth at the University of Oslo, challenging a claim like this is not a simple thing.

[Nils Christian Stenseth]

I usually say to my students that if you want to have enemies within science, study plague because there are so many strong personalities and There are so many different opinions and they hate each other.

[Stephen Dubner]

The standard epidemiological model of the Black Death is that humans were exposed to the plague by rats who had been bitten by diseased fleas. But in 2018, Stenseth and his colleagues published a paper in the Proceedings of the National Academy of Sciences where they presented a different model. Despite the historical significance of the disease, they wrote, the mechanisms underlying the spread of plague in Europe are poorly understood. While it is commonly assumed that rats and their fleas spread plague, there is little historical and archaeological support for such a claim. We show that human ectoparasites, like body lice and human fleas, might be more likely than rats to have caused the rapidly developing epidemics. And what is Stenseth's evidence that rats were not responsible for the Black Death? He and his co authors looked at plague death rates from the 1300s to the 1700s, drawn from census records and historical accounts from cities including London, Barcelona, Florence. Based on the velocity at which the plague spread in these places, Stenseth concluded the human parasite model was much more likely than the rat parasite model.

[Nils Christian Stenseth]

It became very clear that rat could not have played a major role in the spread of plague in Europe.

[Ed Glazer]

One of the reasons why the rat led. Plagues need to be slow is the rat has to die before the flea leaves the rat. So the flea stays on the rat as long as the rat's alive. It's only when the rat dies that the flea then hops to a human host.

[Stephen Dubner]

And that is Ed Glazer.

[Ed Glazer]

I'm the Fred and Eleanor Glimp professor of Economics at Harvard University.

[Stephen Dubner]

That's right. Glaser is an economist, not an epidemiologist or a biologist or even a rat expert. But Glaser is an expert in cities, which is where rats thrive and where disease spreads. And when we told him we were working on this rat series, he did some extra credit reading.

[Ed Glazer]

I have now read enough in various academic journals that it seems like we have a consensus this was not by and large rat carried. They do seem to have played a critical role in the third bubonic plague explosion, although probably not in the first two.

[Stephen Dubner]

So having determined that, that there is at least some guilt of the rat in at least the third pandemic, but perhaps not the most famous, the Black Death. How would you say that the modern day reputation of the rat has been affected by or informed by its implication past disease carrying.

[Ed Glazer]

So blaming the rat is pretty much, you know, game over in terms of the rat's global reputation. I Think we should also just object to using the word guilt on rats. It's not like they know what's going on. They're dying too. I mean, let's push the guilt where it belongs. Let's go to Yersinia Pestis itself. That's where the evil lies.

[Stephen Dubner]

Glaser is the author of a book called Triumph of the City. How Our Greatest Invention Makes Us Richer, Smarter, Greener, Healthier and Happier. And the fact is that cities and rats seem to be an inevitable pairing. In the ruins of Pompeii, there were rats. To estimate the size of human populations in ancient cities, modern scientists use archaeological evidence of rat populations.

[Ed Glazer]

When cities are at their best, they do enable people who are outsiders to thrive. It's hard to imagine more of an outsider than a rat.

[Stephen Dubner]

To an economist, do rats present an obvious economic angle or maybe even multiple ones?

[Ed Glazer]

Well, sure. Rats are, you know, they're agents of usually negative externalities within cities. Right. So they're part of what enables diseases to spread across people and consequently they're somewhat risky. I don't know what positive things we get out of rats, but there probably are some in the same sense that, you know, the four pest program that Mao followed, he thought getting rid of the sparrows was great. It turns out the sparrows kept the locusts under control. And without the sparrows, the locusts went haywire and destroyed the crops, leading to a massive famine.

[Stephen Dubner]

Now, there was reportedly a big surge in rat population in New York city starting around 2020. I'm curious to know your thoughts on why. Obviously, Covid is a factor to consider. There were, in the aftermath of COVID the eruption of hundreds, maybe thousands of outdoor dining sheds outside of restaurants. So I'm curious what you think of all that.

[Ed Glazer]

Certainly Covid seems to have played some kind of a role. I mean, there were a whole bunch of city services that diminished because people were working from home or just weren't going in and so forth. So I wouldn't rule that out completely. Certainly changes in the food availability seem likely to be quite important. This would feel a lot better with some kind of measurement.

[Stephen Dubner]

Now, if I recall correctly, you were born and raised in Manhattan. Indeed, one could imagine that rats destroy or degrade the reputation of a city like New York. Do you put much stock in that argument?

[Ed Glazer]

Oh, that seems a little bit far fetched to think that it's such an important deal. I would say that what rats effectively do is they reduce the density level for people and so they tend not to be density multipliers about the good things about cities which are, you know, enabling us to learn from one another. I've never heard of a rat carrying a message that was effectively interpreted. But they do seem to carry the negative stuff that we get from being close to one another.

[Kathy Karate]

There's an economic impact as well. So thinking about damages to property, they.

[Stephen Dubner]

Like to chew wires, don't they?

[Kathy Karate]

They like to chew everything that is.

[Stephen Dubner]

New York City rat czar, Kathy Karate.

[Kathy Karate]

That is literally their nature to chew. They chew through holes and foundations. They can damage different food sources. 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. 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.

[Stephen Dubner]

Although from what I've seen, the Last number is 2023. It looked like in New York City, 24 people were diagnosed with leptospirosis, the highest number of reported cases in a single year. But this city of over 8 million. So that sounds like a pretty minor threat.

[Kathy Karate]

No, I'm with you. It's certainly not the highest public health risk we have across, you know, our city or the globe.

[Stephen Dubner]

But that's also people I understand dogs get leptospirosis as well, and that maybe is a bigger problem for New Yorkers.

[Kathy Karate]

Yes, dogs have a vaccine for leptospirosis. There's other, I'd say unrealized potential public health risks when it comes to 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 hosts. Because rats are so close to us in where and how they live, that threat just gets higher and higher.

[Stephen Dubner]

Coming up after the break, is the threat of disease really what this is about?

[Bethany Brookshire]

The fact that we're so quick to blame the rat says a lot about us.

[Stephen Dubner]

I'm Stephen Dubner, this is Freakonomics Radio, and we will be rat back. I'm Sorry, we will be right back. Freakonomics Radio is sponsored by Mint Mobile. Do you like your money? Traditional big wireless carriers also like your money. If you're tired of crazy high wireless bills and bogus fees, Mint Mobile might be right for you with plans as low as 15 bucks a month. All plans come with high speed data and unlimited talk and text delivered on the nation's largest 5G network. Use your own phone with any Mint Mobile plan and bring your phone number along with all your existing contacts. Ditch overpriced wireless and get three months of premium wireless service from Mint Mobile for 15 bucks a month. If you like your money, Mint Mobile is for you. Shop [e-mail] freak that's mintmobile.com freak upfront payment of $45 for 3 month 5 gigabyte plan required equivalent to $15 a month new customer offer for first 3 months only, then full price plan options available, taxes and fees extra. See Mint Mobile for details.

[Eric Adams]

Pilots know that weather factors like pop up storms, turbulence and unexpected icing can turn a routine flight into a challenge. But what if you had satellite delivered weather data giving you the full picture of what's around you directly on your Tablet or display? SiriusXM Aviation brings you coast to coast high resolution weather info including radar, winds, icing, TFRs, pireps and more without altitude limitations or line of sight restrictions. Plus it includes features not found on Ads B such as storm tracks, echo tops and both cloud to cloud and cloud to ground lightning. SiriusXM's aviation services are compatible with the Foreflight and Garmin pilot apps. You can also add SiriusXM Entertainment and listen to ad free music plus sports talk, comedy news and more. While you fly. Fly confidently, knowing you have the best information available to make decisions in flight. Visit SiriusXM.com to learn more.

[Stephen Dubner]

It's a cold day here in Alaska, but there's one animal seemingly unaffected, bright eyed and determined enters the husky. Observe as they go up the mountain.

[Nils Christian Stenseth]

Guided by pure instinct.

[Stephen Dubner]

They are truly amazing masters of this wilderness. But even these amazing pets can't sign up for Lemonade Pet Insurance. You can sign up [e-mail] Amazing a rat is a rodent, a member of the order Rodentia, which contains over 2,000 species. Nearly half of all mammals are rodents. They are famous for their gnawing ability, which is carried out by large pairs of of upper and lower front incisors. Squirrels, mice, beavers, hamsters, prairie dogs, porcupines, they are all rodents. But it seems fair to say that rats are the most despised member of this order. Why? For that, let's go back to Bethany Brookshire.

[Bethany Brookshire]

I'm the author of the 2022 book How Humans Create Animal Villains.

[Stephen Dubner]

Talk about just the title itself and what kind of work you're asking that word pests to do.

[Bethany Brookshire]

Oh, man, pests. The word does so much work in our society, just in general. It has become a word for animals that are not where we want them to be. And that was one of the things that I became really fixated on, is the fact that the animals that we hate are so subjective. The animals are just being animals. They're about us. They're about where we think animals belong and what we think those animals should be doing.

[Stephen Dubner]

Do you think the rat has been unfairly tarnished its reputation over time by having been associated with the Black Death?

[Bethany Brookshire]

I don't know that it's been unfairly tarnished. I certainly think there was probably a place for it. I do think the fact that we're so quick to blame the rat says a lot about us. Because the reality is the thing that causes most diseases in humans, like communicable diseases, is other humans. Right? We're the major vectors of disease to each other. If we've learned anything from the COVID 19 pandemic, it is that humans do.

[Stephen Dubner]

Like to assign blame to other animals. But as Brookshire points out, the blame can be assigned somewhat randomly. Consider the rabbit. The rabbit is not a rodent, although it used to be classified as such. Today it is considered a lagomorph, since it has four upper incisors, not two. For most people, the rabbit is thought of as I believe the technical term is cute. It's fluffy, it hops, it has facial features that kind of look like a human baby. If we think of rats as trash eaters, we think of rabbits as carrot nibblers. So cute. But not everywhere is the rabbit considered so benign. In Australia, where rabbits nibble some $125 million worth a year of agricultural crops, there is a new rabbit czar tasked with curbing the Australian bunny population. In her book, Bethany Brookshire writes about many other animals who are considered pests in some circumstances, even if they don't des and elephants and coyotes and the well known bird that some people today call rats with wings.

[Bethany Brookshire]

The pigeon became domesticated around 8,000 years ago, we think, which makes it one of the earliest domesticated birds. Pigeons were cornerstones of many societies. They were incredibly important. Not just for food, though. We absolutely ate them. If you've never had squab I highly recommend. It's delicious. We used them as messengers, and in fact, we decorated pigeons that served in war. Pigeons were used to carry messages. And one of my favorite things is that pigeons were the foundation of modern journalism.

[Stephen Dubner]

Sorry.

[Bethany Brookshire]

Yeah.

[Stephen Dubner]

How so?

[Bethany Brookshire]

When the wire service Reuters started, it was not on a wire. It was on the wing. It was on the pigeon because Reuters figured out he could fly hot stock tips to and from Aachen and beat the train by two hours. And of course, we also use them for their poop because pigeon poop is excellent fertilizer. And there's wonderful dovecotes. You can still see some of them today, developed by the ancient Persians that are these beautiful bell shapes so that all the poop falls to the bottom and you can scoop it.

[Stephen Dubner]

Okay, so that history of pigeons is really interesting. But now pigeons, they're what, just another pest, Essentially, Yeah.

[Bethany Brookshire]

There's a wonderful piece of work by Colin Jarrelmak, who actually documented the fall of the pigeon in the public eye via articles in the New York Times over a century. And he was able to document that over about a hundred years, pigeons went from noble, innocent, beautiful, to rats with wings. You know, we no longer needed fertilizer. We have chemical fertilizer. We don't need messengers anymore. We have email, and we don't need squab anymore. We have chicken.

[Stephen Dubner]

How would you say that the history of the human pigeon relationship compares with the history of the rat human relationship?

[Bethany Brookshire]

I would say the history of the human pigeon relationship differs in that we once had a use for the pigeon. I think of the pigeon as kind of the outdated cell phone of the animal world. Right. We used to have such a use for them, and now we don't. And we can't fathom why they won't go away. It's so sad.

[Stephen Dubner]

Okay, and if I were to ask you to summarize the downsides and the upsides of rats generally, how would you characterize that?

[Bethany Brookshire]

Well, there are plenty of downsides associated with rats. People don't like them. They find them both physically and psychologically really stressful. People who live very closely with rats, it's awful. No one should have to live that way. Rats give people feelings of unsettledness. Right. They are very associated with our feelings of disgust. And I'm saying that in terms of Western cultures, in terms of, like, the global north, other cultures do not associate rats with disgust.

[Stephen Dubner]

Give me an example of where rats are not thought of as disgusting.

[Bethany Brookshire]

So the temple of Karni Mata. It's located in Deshnoge India. This temple houses around 25,000 black rats. And those rats are considered sacred. They are holy. I got to speak to some of the people who help run the temple, who cook the food for the rats. It's a beautiful temple. It has solid silver doors carved with rats. There are beautiful marble floors for the rats. The rats drink from beautiful, decorated bowls of milk, huge bowls of milk. They eat a wonderfully healthy diet. They get whole wheat bread, like whole bran. They get fruit, vegetables. And people come to make fire and food offerings to these rats. It's because the rats are not considered to be real rats. The rats are reincarnations of people. So the legend is that this woman, Carni Mata, grew up in that area. And she grew up to be a sage. She had mystical powers. And so when her sister's son passed away, he drowned while playing. Her sister brought her the boy and begged her to bring him back. And Karni Mata interceded with Yama, the God of death. And Yama said, okay, the people from your family will no longer die. They will be reincarnated as rats. And then those rats, when they die, will again be reincarnated as people. And so now that temple, the family does still worship there, and it has been several hundred years, but other people, devotees, worship there as well because they believe that they will also be blessed if they are devoted enough to be reincarnated as these rats.

[Stephen Dubner]

What would you say are the drivers of the difference between one place or one culture and another one in which the rat is looked at as just disgusting, a menace, dangerous, scary, et cetera, and one where it's not? What constitutes that difference, do you think?

[Bethany Brookshire]

I would say there are a couple of things. There is one angle that's very cultural. Right. I ended up interviewing for my book a bunch of people who worked in biblical scholarship. We ended up talking about translations and our understandings of things like Genesis. And God gave people dominion over the animals.

[Stephen Dubner]

It's a big line. Yeah.

[Bethany Brookshire]

And that has become very deeply ingrained in many of our cultural ideas of what we should be able to control and how we should be able to control it. I would say that's one of the reasons that we hate these animals, is because we expect animals around us to fail. We are prepared for that. We move into an area, we pave it over. We put up a Walmart, a Target, a Starbucks, a McDonald's, what have you, and we expect the animals to leave. And then we wring our hands. We are so upset. We have killed off this beautiful species. This species becomes beautiful, it becomes charismatic, it becomes this wonderful thing. And look at the horrible stuff we've done to it. But when an animal is still there, we're kind of mad. We don't like it. It's now where we've decided it doesn't belong, even if it always lived there. Now it's our space. You don't belong there anymore. And we get really upset, especially if the animals begin to thrive, and especially if they thrive off things we value, right? Our gardens, our crops, our cats. We really hate them. We hate their success because their success feels like our failure to the animals.

[Stephen Dubner]

That we call pests. What are humans? Are we just, you know, pests that text and build parking lots?

[Bethany Brookshire]

That's actually something I got a lot when I was writing the book, is it's humans. Humans are the real pests. We're the ones invading the world and taking it over and making it awful. I think that's too easy because it's the sort of thing that makes you fling up your hands and be like, oh, there's nothing I can do. We have choices in the way that we treat other animals, and we have choices in the way we treat each other, and we don't need to live the way that we always have.

[Ed Glazer]

So I think it is certainly true that the innate human reaction to rats, I don't know why, is largely revulsion.

[Stephen Dubner]

That, again, is the economist Ed Glazer.

[Ed Glazer]

Certainly when you see them in an urban context, surrounded by trash, right? So you associate the rats with the filth, with drinking the water in the subway. Right. It's hard not to think of that as being sort of awful, since rats.

[Stephen Dubner]

Are no longer a big disease vector, at least for now, in most places. Do you think our frightened view of them is simply outdated? And that for the most part, rats are, yes, a negative externality of humans in cities, but a really minor one that we shouldn't worry so much about.

[Ed Glazer]

I think it's probably pretty small. That being said, I would still probably be in favor of policies that keep the rat population manageable in the sense that who knows what happens if you let it get incredibly vast? Who knows what new diseases occur or what spreads across things? So I think. I think some control, but not making a fetish out of complete eradication.

[Stephen Dubner]

So, Ed, let's play a quick game of word association. When I say rats, you say, what?

[Ed Glazer]

Cuddly?

[Stephen Dubner]

Come on, now, you're just trying to make me happy now, aren't you?

[Ed Glazer]

You know, it's hard not to think that rats have gotten something of a bad rap. They certainly are not healthy to have in vast numbers around you. But, you know, it's a very urban species and I tend to like that they sort of co live with humans. They're in some sense our natural city partners.

[Stephen Dubner]

I want to run past you at a couple of titles we're considering for this series. Let me know what you think. One, is the Exoneration of the Rat too much?

[Ed Glazer]

It feels a little strong. It feels a little strong because it's not like this thing does not do anything but something in that neighborhood. Sounds good.

[Stephen Dubner]

Could I interest you in Sympathy for the Rat?

[Ed Glazer]

Yes, yes. I love it. I love it. And the echo, of course, with the Rolling Stones is great.

[Stephen Dubner]

Although the Rolling Stones sympathy. This is sympathy for the devil. The devil is the narrator of that song. You know, I shouted out who killed the Kennedys? When after all, it was you and me. So it's not the purest sympathy, let's say. Do you still like this angle?

[Ed Glazer]

I do, I do. I think in general, having sympathy for a creature that, you know, coexisted with us, that suffers many of the same negative sides from cities as we do, that enjoys many of the same positive sides of cities that we do, the ability to create this ecosystem, I think that's a very worthy aim. And even if we do have to control the rat, not viewing it with so much horror, but rather viewing it as being, you know, our urban partner, seems like it makes more sense.

[Stephen Dubner]

Coming up next time in part two of Sympathy for the Rat, we will talk about how to control this urban urban partner of ours.

[Kathy Karate]

I believe that the single biggest swing that you can take at the rat problem in New York City is getting the trash bags off of the streets.

[Stephen Dubner]

And we'll explore the city with a master of the urban rat. Rodents are really great examples of.

[Ed Glazer]

Work hard and you'll be successful.

[Stephen Dubner]

And we'll visit a place that claims to be nearly rat free.

[Bethany Brookshire]

People are desperate and they want to.

[Kathy Karate]

Know what our secret is.

[Stephen Dubner]

That's next time on the show. Until then, take care of yourself. And if you can, someone else too. Freakonomics Radio is produced by Stitcher and Renbud Radio. You can find our entire archive on any podcast app. [e-mail] where we publish transcripts and show notes. This episode was produced by Zach Lipinski with help from Dalvin Abuaji. Special thanks to Freakonomics Radio listener Jason Weeks for suggesting this topic. The Freakonomics Radio Network staff also includes Alina Coleman, Augusta Chapman, Eleanor Osborne, Ellen Frankman, Elsa Hernandez, Gabriel Roth, Greg Rippon, Jasmine Klinger, Jeremy Johnston, John Schnarz, Morgan Levy, Neal Carruth, Sarah Lilly and Teo Jacobs. Our theme song is Mr. Fortune by the Hitchhikers. Our composer is Luis Guerra. As always, thank you for listening.

[Kathy Karate]

Whenever I do calls at home, my dog thinks it's an opportunity to voice his opinion as well.

[Bethany Brookshire]

The Freakonomics Radio Network the Hidden side of Everything Stitcher.

[Eric Adams]

Pilots know that weather factors like pop up storms, turbulence and unexpected icing can turn a routine flight into a challenge. But what if you had satellite delivered weather data giving you the full picture of what's around you directly on your Tablet or display? SiriusXM Aviation brings you coast to coast high resolution weather info including radar, winds, icing T, TFRs, Pireps and more without altitude limitations or line of sight restrictions. Plus it includes features not found on Ads B such as stormtrax, Echo Tops and both cloud to cloud and cloud to ground lightning. SiriusXM's aviation services are compatible with the Foreflight and Garmin Pilot apps. You can also add SiriusXM Entertainment and listen to ad free music plus sports talk, comedy news and more. While you fly, fly confidently knowing you have the best information available to make decisions in flight. Visit SiriusXM.com aviation to learn more.