Why Does Everyone Hate Rats? (Update)

Summary

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Freakonomics Radio: "Why Does Everyone Hate Rats? (Update)"

Host: Stephen J. Dubner
Originally aired: April 22, 2026

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Overview

With springtime in New York City and rats emerging in force, Stephen Dubner revisits and updates one of Freakonomics Radio’s most popular episodes: an exploration of humans’ complex relationship with rats. The episode investigates the roots of rat hatred, their actual impact on public health, the social, economic, and psychological reasons behind our collective aversion, and surprising cultural differences in their reputation. With fresh data and new perspectives, Dubner and a lively cast of guests probe the surprising, often misunderstood realities of urban life’s most reviled animal.

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Key Discussion Points and Insights

1. Rats and Urban Life: The New York City Context

• Springtime Means Rats: Warmer weather in NYC correlates with increased rat activity ([01:03]).
• Government Action: NYC created a new position—a so-called “Rat Czar” tasked with rodent mitigation.
• Eric Adams' Crusade: Former Mayor Eric Adams positioned himself as fervently anti-rat, highlighting the trauma many New Yorkers associate with rats ([02:05]).
  • “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.” — Eric Adams ([02:46])

Kathy Karate: The “Rat Czar” Experience

• Background: Kathy Karate, NYC’s first Rat Czar, describes her unconventional path—from childhood activism (petitions to clear out rat harborage) to citywide leadership ([06:01]-[07:03]).
• Sanitation is Key: “The key to pest management, any pest management, first and foremost, is sanitation.” — Kathy Karate ([07:33])
• Challenges in Counting Rats: Estimates of NYC’s rat population vary dramatically; there’s no official census ([08:11]).
• Commensal Species: Rats thrive where humans do, feeding off our waste and infrastructure ([09:05]).

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2. Understanding Rats: Brains, Behaviors, and Adaptation

• Intelligence and Adaptability

  • Rats are clever, exhibiting adaptability—testing new food for safety and showing signs of empathy and laughter ([10:07]-[10:29]).
  • “In terms of adaptability to survive, there’s few species greater. … No one except humans exploits an urban space better.” — Kathy Karate ([10:26])

• Species and History:

  • Two main types: the brown rat (Rattus norvegicus) and black rat (Rattus rattus).
  • “Because everybody who hates rats wants to name them after somebody they don’t like.” — Bethany Brookshire on the naming of the “Norway rat” ([11:36])

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3. Rats, Disease, and the Truth About the Black Death

Historical Villainy

• Changing Reputation: Rats weren’t always deemed “disgusting”—their image as disease carriers arose in the 18th-19th centuries ([12:05]).
• Pandemics and Plague:
  • Bubonic plague is a disease of rats and fleas that occasionally jumps to humans with catastrophic effects ([14:08]).
  • “The plague is technically not a disease of humans. It is a disease of rats and fleas that happens to spill over…” — Bethany Brookshire ([14:20])
  • Plague still exists globally but is exceptionally rare in the modern U.S.

Revisiting Blame: Did Rats Cause the Black Death?

• Scientific Debate: Nils Christian Stenseth and colleagues suggest that human ectoparasites (lice, fleas) may have been the primary disease vectors, not rats ([19:41]-[21:10]).

  • “It became very clear that rat could not have played a major role in the spread of plague in Europe.” — Nils Christian Stenseth ([21:10])

• Rate of Transmission: The traditional spread via rat-flea-human is too slow to explain historical patterns; human-to-human transmission via body lice and fleas is more plausible ([21:21]).

Modern Public Health Impact

• Leptospirosis and Other Threats:

  • Leptospirosis (via rat urine) is a real but minor threat (24 NYC cases in 2023; pop. >8 million) ([26:10]).
  • Rats harbor other pathogens, and proximity does pose theoretical risks ([26:38]).

  “There’s also a public health risk. Leptospirosis is one of the more famous illnesses associated with rats… but it’s certainly not the highest public health risk we have across our city or the globe.” — Kathy Karate ([26:10], [26:25])

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4. The Psychology and Sociology of Rat Hatred

What Makes a Pest?

• Subjective Definitions:
  • 'Pest' is a label we assign to animals who are, as Bethany Brookshire puts it, “not where we want them to be” ([30:04]).
  • “The fact that we’re so quick to blame the rat says a lot about us. The thing that causes most diseases in humans, like communicable diseases, is other humans.” — Bethany Brookshire ([30:39], [31:15])

Cultural Differences

• Different Attitudes:
  • In India, the Karni Mata temple reveres and feeds 25,000 sacred rats—believed to be reincarnated ancestors ([35:34]).
  • In contrast, Western urban cultures focus on disgust, psychological stress, and a sense of violation when rats are present ([35:00]).

Historical Parallels: Other “Villainous” Animals

• Pigeons’ Rise and Fall:
  • Pigeons were once valued for food, messaging, and fertilizer. Now, they’re pejoratively “rats with wings” ([33:39]-[34:20]).
  • “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.” — Bethany Brookshire ([34:28])

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5. Economics, Cities, and Rats

Negative Externalities and Adaptation

• Costs and Consequences: Rats damage property and infrastructure, which imposes public and private costs ([25:16]).
• Cities as Ecosystems:
  • “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.” — Ed Glazer ([23:17])
  • Rats and disease “tend not to be density multipliers about the good things about cities... but they do seem to carry the negative stuff…” ([24:50])

Should We “Exonerate” the Rat?

• Sympathy vs. Eradication:

  • The fear and disgust we feel may be outdated; disease risk is low in modern contexts.
  • “I think some control, but not making a fetish out of complete eradication.” — Ed Glazer ([40:50])

  “It’s hard not to think that rats have gotten something of a bad rap. … They’re in some sense our natural city partners.” — Ed Glazer ([41:16])

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Notable Quotes & Memorable Moments (with Timestamps)

• Eric Adams’ personal crusade:
  “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.” — Eric Adams, ([02:16])

• On sanitation and pest management:
  “The key to pest management, any pest management, first and foremost, is sanitation.” — Kathy Karate, ([07:33])

• Rats as commensals:
  “They are thriving and existing because of the plate we’ve set for them in our urban spaces.” — Kathy Karate, ([09:05])

• Historical bias in the Norway rat’s naming:
  “Because everybody who hates rats wants to name them after somebody they don’t like.” — Bethany Brookshire, ([11:36])

• Reframing the Black Death:
  “It became very clear that rat could not have played a major role in the spread of plague in Europe.” — Nils Christian Stenseth, ([21:10])

• On our hatred of rats:
  “We really hate them. We hate their success because their success feels like our failure.” — Bethany Brookshire, ([04:24]; [38:03])

• Animals as pests—only in the eye of the beholder:
  “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.” — Bethany Brookshire, ([30:04])

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Important Timestamps for Key Segments

• [01:03] Introduction—Springtime rats in NYC and the new "Rat Czar"
• [02:05 – 02:57] Eric Adams on his hatred of rats and civic trauma
• [06:01 – 07:03] Kathy Karate’s early activism and start in rat mitigation
• [09:05 – 10:26] Rats as commensal species: their relationship to humans
• [12:05 – 14:08] Bethany Brookshire on rat reputation, plague, and disease history
• [19:41 – 21:10] Nils Stenseth’s research exonerating rats from the Black Death
• [23:17 – 25:16] Ed Glazer discusses rats as urban “outsiders” and economic actors
• [30:04 – 31:15] Bethany Brookshire on the subjectivity of “pests” and blame
• [35:34 – 37:24] The sacred rats of Karni Mata temple in India
• [40:50 – 42:20] Ed Glazer on sensible rat policies, sympathy for rats
• [42:52 – 43:36] Recent rat mitigation successes and ongoing city plans

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Conclusion

The episode deftly shifts the lens from rat eradication campaigns and public health fears to a deeper examination of human psychology, cultural differences, and the unintended consequences of our urban coexistence with a highly successful animal. Listeners are encouraged to question whether our hostile attitudes toward rats are truly justified today—and to consider what our relationship with pests might say about us.

Memorable moment:
“It’s hard not to think that rats have gotten something of a bad rap... They’re in some sense our natural city partners.” — Ed Glazer ([41:16])

Final note:
If you enjoyed this conversation, the episode is part one of a three-part series about rats—find more at freakonomics.com/rats.

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Transcript

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[Stephen Dubner]

Hey there, it's Stephen Dubner. And it is springtime in New York City, which means the trees are greening up, the sidewalk cafes are crowded, and the rats are coming out. So we figured this was the moment to bring you an update of an episode we first published last year, a very popular episode called why Does Everyone Hate Rats? We have updated facts and figures as needed. 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. What kind of government job requires wholesale slaughter? Here is the man responsible for this listing.

[Eric Adams]

Rats do something to traumatize you. And I hate rats.

[Stephen Dubner]

That is Eric Adams, who at the time was mayor of New York City.

[Eric Adams]

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.

[Stephen Dubner]

Adams made a lot of headlines when he was in office, like an indictment on federal criminal charges, including bribery and wire fraud, although those were ultimately dismissed. Recently, Adams became a citizen of Albania. During his one term as mayor, Adams was fervently anti rat.

[Eric Adams]

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.

[Stephen Dubner]

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 Verdant 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 back. But is wholesale slaughter really the way to go? Today on Freakonomics Radio, that is one of the many rat questions that I'm eager to answer. 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 our 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]

And we'll hear from what you might call the rat exonerators.

[Ed Glazer]

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

[Stephen Dubner]

Why does everyone hate rats? It's coming up right 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 Kathy Karate, who at the time of this interview, was New York City's rat czar. She has since left that position and now works for the city's housing authority.

[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 go to 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 facilities 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 rats. They're commensal, meaning they sit at the table with us.

[Stephen Dubner]

What is that word 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?

[Bethany Brookshire]

In a way.

[Kathy Karate]

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 monitor, see if there's ill effects. So 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, Rattus rattus, which likely originated in India, and then the brown rat that we are familiar with, Rattus norvegicus, 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. Ratis 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, and 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

[Stephen Dubner]

effects 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 Netflix show set during the Black Death, a massive swarm of rats come together to spell out the title. A 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.

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[Bethany Brookshire]

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[Ed Glazer]

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[Stephen Dubner]

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 Stenseth 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, Stentseth 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 Elon 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 in 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 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, 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.

[Stephen Dubner]

They like to chew wires, don't they?

[Kathy Karate]

They like to chew everything.

[Stephen Dubner]

That's former 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 numbers, 20, 23, 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.

[Nils Christian Stenseth]

Foreign.

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[Bethany Brookshire]

So good, so good, so good.

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[Stephen Dubner]

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 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 the 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 Berkshire 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 deserve to be, like snakes and elephants and coyotes. And the well known bird that some people today call rats with wings, the

[Bethany Brookshire]

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?

[Bethany Brookshire]

Essentially, yeah. There's a wonderful piece of work by Colin Jarlmak, 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 Carni 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.

[Stephen Dubner]

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, 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]

So as New York City's war on rats led to any real change, maybe Last year the Department of sanitation reported a 20% year over year decline in rat sightings. And Eric Adams successor as Mayor Zoran Mamdani is keeping the war going. He has a plan to achieve city wide trash containerization by the end of 2031. I hope you enjoyed this update from our archives. If you'd like to hear even more about rats, I have I have great news for you. This episode was part one of a three part series. You can find the other episodes on any podcast app. [e-mail] rats we will be back very soon with a brand new episode. Until then, take care of yourself and if you can, someone else too. Freakonomics Radio is produced by Renbud Radio. This episode was produced and updated by Zach Lipinski with help from Dalvin Abuaji. It was made mixed by Jasmine Klinger with help from Jeremy Johnston. Special thanks to Freakonomics Radio listener Jason Weeks for suggesting this topic. The Freakonomics Radio Network staff also includes Augusta Chapman, Ellen Frankman, Elsa Hernandez, Gabriel Roth, Hilaria Montenacort, Jake Loomis, Mandy Gorenstein, Peter Madden, and Teo Jacobs. Our theme song is Mr. Fortune by the Hitchhikers and 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

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[Bethany Brookshire]

so good, so good, so good.

[Nordstrom Rack Advertiser]

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[Bethany Brookshire]

How did I not know Rack has Adidas? Why do we rack for the hottest deals. Just so many good brands.

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