622. Why Does Everyone Hate Rats?

Episode Summary

Executive Summary: This episode launches a three-part Freakonomics Radio series on rats, centered on New York City’s rat czar Kathy Koraty and the question of whether rats deserve their brutal reputation. It explores rat history, disease myths vs. evidence, urban ecology, and cultural attitudes, arguing that humans create many of the conditions that make rats thrive—and that total eradication is less realistic than managed coexistence.

Main Topics: New York City’s rat czar and the city’s anti-rat campaign (Priority: 5/5): The episode opens with Eric Adams’ hyperbolic rat-hunting job posting and introduces Kathy Koraty, NYC’s director of rodent mitigation, who explains the city’s sanitation-focused strategy and the challenge of controlling rats in a dense urban environment. Rats as urban survivors and commensal animals (Priority: 5/5): Rats are portrayed as highly adaptive animals that exploit human-built environments, thrive on human waste, and live alongside people as commensals—benefiting from the same urban systems humans create. Disease, plague, and the rat’s bad reputation (Priority: 5/5): The episode examines the historical link between rats and plague, especially bubonic plague, but notes that modern science increasingly challenges the idea that rats were the main driver of the Black Death in Europe. Scientific debate over the Black Death’s transmission (Priority: 4/5): Ecologist Niels Christian Stenseth and economist Ed Glaeser discuss evidence suggesting human-to-human transmission may have played a larger role than rats in the medieval plague, and that the scientific debate remains contentious. Humans create ‘pests’ through cultural framing (Priority: 5/5): Science journalist Bethany Brookshire argues that 'pest' is a subjective category: animals become villains when they conflict with human expectations of where they should live and what they should do. Rats, cities, and economics (Priority: 4/5): Ed Glaeser frames rats as a negative externality of cities, affecting public health, property, and mental well-being, while cautioning against making eradication a fetish rather than pursuing manageable control. Cultural variation and rat symbolism (Priority: 4/5): The episode contrasts Western disgust with reverence in places like the Karnimata temple in India, showing that rats can be sacred, useful, or symbolic depending on cultural context.

Key Arguments: Rats are not simply independent villains; they thrive because human behavior and urban sanitation create abundant food and shelter for them. New York’s rat problem is fundamentally a waste-management and sanitation problem, not just a pest-control problem. The common story that rats caused the Black Death is likely oversimplified; evidence suggests human parasites and human-to-human spread played a major role, especially in the famous 14th-century pandemic. Even if rats were involved in later plague outbreaks, blaming the rat alone is scientifically and morally misleading. The word 'pest' reflects human preferences and boundaries more than any objective animal quality. Rats evoke disgust and anxiety, but their reputation is shaped by culture, history, and urban design as much as by biology. Complete eradication is unrealistic; the sensible goal is keeping rat populations manageable. Cultural attitudes toward rats vary widely, and in some places they are sacred rather than despised.

Data Points: Anniversary of Freakonomics: 20 years - Stephen Dubner notes the 20th anniversary of the original Freakonomics book. Anniversary of Freakonomics Radio: 15 years - Dubner notes the 15th anniversary of Freakonomics Radio. NYC rat czar job posting year: Fall 2022 - The controversial rodent-mitigation job listing was posted on a New York City government website. Federal charges against Eric Adams: 5 charges - The transcript notes Adams was indicted on five federal criminal charges including bribery and wire fraud. Public school buildings served in Karachi/Koraty's prior work: 120 buildings - Koraty said she visited 120 school buildings for waste and rat mitigation work. Estimated rats in NYC: 3 million (example estimate) - A pest-control estimate is mentioned, but the episode stresses there is no reliable census. Number of rodent species: Over 2,000 species - A general taxonomy note on rodents. Share of mammals that are rodents: Nearly half - The episode explains the broad rodent order. Rat species mentioned: 2 main species - Black rat and brown rat are identified as the major species discussed. Plague pandemics in recorded history: 3 major pandemics - The episode cites the Plague of Justinian, the Black Death, and the ongoing third pandemic. Black Death mortality: Half of the European population - The Black Death is described as killing roughly half of Europe in a year or two. Plague cases today: A few hundred per year - The transcript says plague still occurs globally in small numbers. Reported U.S. plague cases: Fewer than a dozen a year - Current U.S. incidence is described as very low. NYC leptospirosis cases in 2023: 24 people - The mayor’s anti-rat concerns are contrasted with this relatively small public-health number. Rat temple population: Around 25,000 black rats - The Karnimata temple in India houses a large sacred rat population. Rabbit crop losses in Australia: $125 million a year - Used to show that animals seen as cute elsewhere can be pests in different contexts.

Pivotal Quotes: "“The ideal candidate ... is highly motivated and somewhat bloodthirsty ... including data collection, technology innovation, and wholesale slaughter.”" — Stephen Dubner quoting the NYC job listing: Opening setup for the city’s rat-control campaign and the tone of anti-rat rhetoric. "“We hate their success. Because their success feels like our failure.”" — Bethany Brookshire: Explaining why humans despise rats and other animals labeled as pests. "“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 ... not making a fetish out of complete eradication.”" — Ed Glaeser: Summing up the case for practical control rather than total eradication.

Implications: Listeners are left with a more nuanced view of rats: as products of urban design, sanitation, and human culture. The likely future is better control, not elimination—and less moral panic, more evidence-based coexistence.