Summary of Why Does Everyone Hate Rats? (Update)

Overview of Why Does Everyone Hate Rats? (Update)

This Freakonomics Radio episode (update) revisits the question of why rats are so reviled, combining reporting from New York City’s recent “war on rats” with historical, scientific, economic, and cultural perspectives. Host Stephen Dubner interviews NYC rodent-mitigation officials, scientists, and authors to explain how and why rats thrive in cities, whether they deserve the blame for historic pandemics (especially the Black Death), what public‑health risks they pose today, and how culture shapes our feelings about them.

Key takeaways

• Rats are an urban‑adapted, commensal species (most commonly Rattus norvegicus, the brown/Norway rat, and Rattus rattus, the black rat) that thrive where humans provide food and shelter.
• Sanitation and waste management are the central levers for controlling rat populations; trash on sidewalks and changes in food availability (e.g., pandemic-era outdoor dining, altered city services) affect rat numbers.
• The historical linkage between rats and the Black Death is now debated: recent research suggests human ectoparasites (lice, human fleas) may better explain the rapid spread in medieval Europe, while rats were implicated in the later (19th–20th century) third plague pandemic.
• Modern plague still exists but at low levels (a few hundred global cases per year; single‑digit yearly cases in the U.S.), and other rat‑associated illnesses (e.g., leptospirosis) are rare in a large city like NYC.
• Cultural context matters: some societies revere rats (e.g., the Karnimata temple in India), while others demonize them—“pest” status often reflects human values and utility more than animal behavior.

Topics discussed

• New York City politics and policy

  • Eric Adams’ anti‑rat rhetoric and the high‑profile “Ratsar” job posting.
  • Kathy Karati (NYC’s then director of rodent mitigation) on mitigation strategy: data, tech, sanitation, and community engagement.
  • Mayor Eric Adams’ successor continuing policies; DSNY reported a 20% year‑over‑year decline in rat sightings recently. A plan aims for citywide trash containerization by 2031.

• Biology and behavior

  • Rats’ intelligence, social behavior, and adaptability; examples of behavior like neophobia (avoiding new things) and social testing of food sources.
  • Rodents are a huge order (over 2,000 species); rats are particularly successful in dense human settlements.
  • Species origins: R. norvegicus (brown/Norway rat) and R. rattus (black rat).

• Disease and epidemiology

  • Yersinia pestis is the bacterium that causes bubonic plague; transmission historically involves fleas and rodents.
  • Mechanism described: flea biofilm blocks flea’s esophagus, causing it to regurgitate bacteria while biting and, after the rat dies, seek new hosts.
  • Contemporary debate: Niels Christian Stenseth and colleagues (PNAS 2018) argue plague spread in 14th‑century Europe is better explained by human ectoparasites (lice and human fleas) than rat‑to‑human flea jumps.
  • The third pandemic (late 19th century onward) did involve rats more clearly.
  • Today plague is rare; other rat‑associated pathogens and novel viruses have been detected on urban rats (a point of ongoing research).

• Cultural and historical views

  • Bethany Brookshire (author of Pests) on how societies “create” animal villains; the pigeon’s fall from valued to pest mirrors rat demonization.
  • Example of contrast: Karnimata temple in Deshnok, India, where black rats are sacred and cared for.

Notable quotes and insights

• “They are commensal—meaning they sit at the table with us.” —Kathy Karati, on why rats are uniquely urban pests.
• “We hate their success because their success feels like our failure.” —Bethany Brookshire, on why people resent pest species that thrive in human environments.
• “Blaming the rat is pretty much...game over in terms of the rat’s global reputation.” —Ed Glaeser (economist), noting how association with disease irreversibly damages an animal’s image.
• On plague transmission: scientists argue the speed and pattern of medieval epidemics are more consistent with human ectoparasites than rat‑borne fleas.

Data, facts, and caveats highlighted

• No reliable census of NYC’s rat population exists; street estimates (e.g., “3 million”) are unreliable.
• Plague: a few hundred reported cases globally per year today; generally very few in the U.S.
• NYC 2023 leptospirosis cases: 24 reported (higher than prior years but small relative to an 8+ million population).
• DSNY reported a 20% decline in rat sightings year‑over‑year (context and measurement methods matter).

Practical recommendations / policy implications

• Focus on sanitation first: reduce accessible food and harborage (sealed trash containers, regular street cleaning).
• Containerization of trash (citywide) is a strong structural solution; NYC aims for full containerization by 2031.
• Integrated pest management: monitoring, targeted removal, habitat reduction, public education, and limited use of rodenticides—avoid fetishizing total eradication because complete elimination is impractical and may have unintended consequences.
• Invest in research and surveillance for rodent‑borne pathogens (study of ectoparasites, viral reservoirs).
• Avoid sensationalism; policy and public messaging should be evidence‑driven and culturally sensitive (recognize differing cultural attitudes toward animals).

Further listening / resources

• This episode is the first of a three‑part Freakonomics Radio series on rats — other episodes are available at Freakonomics.com/rats or on podcast platforms.
• Books and research cited include Bethany Brookshire’s Pests and the 2018 PNAS paper by N. C. Stenseth et al. on ectoparasite models of the Black Death.

Credits: updated episode hosted by Stephen Dubner with interviews and reporting from Kathy Karati (NYC rodent mitigation), Bethany Brookshire, Niels Christian Stenseth, and economist Ed Glaeser; produced by Freakonomics Radio.