Super Rats: Rapid Urban Evolution in Large Cities
Rats have evolved rapidly in large cities, such that they are now higher IQ and tougher to kill... compressed evolution.
I recall years ago watching a Vice documentary on “Invincible Super Rats” in large cities that are genetically-resistant to poison… it taught me that big city rats are evolving faster than ever due to extreme environmental pressures such as: rat poison, rat traps, and other predators.
Some are evolving resistance to the poisons, are becoming smarter (knowing how to dodge traps), and developing “super-rat” abilities. How are they evolving so rapidly though?
Compressed evolution:
Wild brown rats (Rattus norvegicus) breed rapidly: About every 3 months under good conditions (some are even faster) which yields ~4 generations per year.
Rats have large litters: Typically 6-12 “pups.”
Abundant food & shelter: Cities provide year-round resources for rats which boost their reproduction rates.
Extreme selection pressures: Cities have rat poisons (e.g. warfarin), rat traps, other predators (e.g. alley cats), and human disturbances.
If we assume ~280 rat generations since the 1950s in a city (since the introduction of warfarin), this likely equals roughly THOUSANDS OF YEARS OF HUMAN-SCALE EVOLUTION (assuming each human generation is ~25 years).
Since beneficial genetics and behaviors (downstream of genetics) confer a survival advantage, you get higher IQ, risk-averse, poison-resistant (or partially-poison-resistant) “super rats.”
As a result they’ve become much more difficult to handle as urban pests… in some cities the “rat problem” is getting worse.
Sidebar: There was a separate Vice documentary about a group of urban rat hunter hobbyists in NYC. They walk around with their pet dogs and see how many city rats they can kill as a group. Gotta wonder how much of a dent they’re putting in the local rat populations.
As of 2025 in the U.S., urban rat infestations have been a major challenge in large cities… particularly: New York City (NYC), Chicago, Los Angeles, and Philadelphia.
And although one would hope that the problem is improving, trends indicate that these infestations are worsening — even with “rodent control” and “sanitation” initiatives.
Why? Many variables at play, including: subpar waste management practices, suboptimal urban design/engineering, increased urban density, climate fluctuations, etc. — and of course the evolution of rats themselves (Antifragile Rats).
I. Evolution of “Super Rats”: Historical Timeline
Rats have coexisted with humans for millennia, but the emergence of so-called “super rats” – rodents with exceptional resilience – is a more recent phenomenon.
The turning point came in the mid-20th century with the widespread use of chemical rodenticides.
1950s: The anticoagulant poison warfarin was introduced around 1950 and quickly became the dominant rat control method. By 1958, less than a decade later, the first warfarin-resistant brown rats (Rattus norvegicus) were documented in the UK.
1960s: Reports of resistant rats and mice spread across Europe, the U.S., Japan, and Australia, indicating that a genetic adaptation was already underway. In response, more potent poisons were developed.
1970s–1980s: Second-generation anticoagulants like difenacoum and brodifacoum (sometimes called “super-warfarins”) were introduced to overcome warfarin resistance. These could kill in a single feed and were effective initially.
1980s: Cases of rats surviving even these stronger poisons began to surface, showing that rodents were again evolving countermeasures.
1990s–2000s: Systematic tracking of resistance waned in some countries, but anecdotal evidence and localized studies suggested the problem was growing.
2010s: Scientists warned that poison-resistant “super rats” had become widespread in certain regions. For example, in 2012 UK researchers found that in parts of England up to 75% of tested rats carried genes for anticoagulant resistance.
Media reports in 2009 had already dubbed Britain’s burgeoning population of immune rodents as “new super rats,” noting a 200% rise in rat numbers since 2007. (Telegraph UK: New ‘Super Rats’ Evolve Resistance to Poison)
The evolutionary shift began soon after warfarin’s introduction in the 1950s and accelerated with each new wave of poison use. Natural selection has, in a matter of decades, produced rat populations that can survive what used to be lethal doses. Today, in the 2020s, many urban areas are essentially fighting the third or fourth generation of “super rats,” with resistance now documented to multiple rodenticides and traditional control methods.
II. Traits Being Selected for in Urban Rat Evolution
The rise of super rats is driven by natural selection for traits that help them survive in human-dominated environments. Key adaptive traits include:
Poison Resistance: The defining trait of “super rats” is genetic resistance to common poisons. Individuals with mutations (especially in the VKORC1 gene) can metabolize or withstand anticoagulants like warfarin, bromadiolone, and difenacoum. When poisoned bait is laid out, susceptible rats die, but those with resistance genes survive and reproduce, spreading the resistance. Over time, this has made entire rat colonies immune to what once was an effective dose. In western England, for instance, what started as a “few percent” resistant rats in the 1960s grew to dominate local populations by the 2010s.
Neophobia & Trap Avoidance: Another trait under selection is behavioral caution. Rats are naturally neophobic (fearful of new objects or foods), and this wariness is reinforced in survivors. If a population is heavily trapped or baited, the bold rats that quickly take new bait are often killed, while the cautious ones that hesitate or sample slowly survive. Over generations this produces more “trap-shy” rats. Historical use of fast-acting poisons demonstrated rats’ learning ability: when rats saw others die shortly after eating a certain bait, they learned to avoid that food. Modern super rats tend to approach unfamiliar foods (including poisoned bait) gingerly or avoid them entirely, making traditional trapping and poisoning less effective. Pest controllers frequently report that today’s city rats can detect and evade poorly placed traps, sometimes snagging the bait without triggering the mechanism. (GridPhilly, 2022)
Problem-Solving Intelligence: Rats have long been known for high intelligence, but urban super rats showcase exceptional adaptability in solving problems to access food and shelter. They can navigate complex sewer systems, remember the locations of traps or danger, and even use tools in simple ways (for example, there are filmed cases of rats dragging sticks to spring traps safely). While all rats are smart, those that excel at outwitting control measures (finding ways around barriers, climbing new obstacles, etc.) gain a survival edge in cities. This means each generation becomes, on average, more adept at exploiting urban niches. Scientists studying city rats note their capability to learn from each other and communicate warnings, effectively “teaching” the colony to avoid hazards. (Rats Capable of Metacognition, 2007)
Nocturnality & Schedule Shifting: City rats are predominantly nocturnal – a trait reinforced by survival pressures. Human activity (and danger to rats) peaks in daytime, so the rats most active at night have higher survival. “Super rats” may be those that have further specialized their activity cycles to avoid humans. For example, in cities with 24-hour activity, some rats shift to pre-dawn or post-midnight foraging to stay unseen. However, when populations explode, rats are sometimes forced to be bolder. There are reports from heavily infested cities of rats scurrying in daylight or entering occupied homes – behavior born of competition and overcrowding rather than preference. Generally, though, the successful urban rats are those that keep a low profile, literally operating in the shadows.
Rapid Reproduction & Early Breeding: High reproductive rate is a natural trait of Norway rats (a female can birth a new litter every 3 months or so). In “super rat” scenarios, this trait is amplified by higher survival rates. Normally, many rats die young due to poison or predators, but if those checks are less effective, more rats live long enough to breed multiple times. Over generations, this can select for individuals that mature faster or breed year-round. In warm urban climates (or with climate change), rats are breeding through winter instead of pausing, leading to population surges. Essentially, any genetic tendencies for faster maturation or larger litters can spread quickly when external mortality drops. The result is a feedback loop: poison-resistant rats survive to produce outsized numbers of offspring, many of which inherit the resistance and continue the cycle. (Urban Rodent Numbers Soar as Climate Heats, 2025)
Physical Robustness: Some experts speculate that surviving poisons and harsh conditions may select for physically larger or more robust rats. A larger rat can absorb a bigger dose of toxin relative to body weight and might survive an otherwise lethal poisoning. Over decades, average size could creep upward in heavily poisoned populations (though data is limited). Certainly, with abundant garbage food and fewer health impacts from sub-lethal poison exposure, urban rats are growing fatter and stronger in many cities. Reports of “giant rats” the size of cats are often exaggerated, but occasional 1+ kg specimens have been found where food is plentiful (such as near grain depots or in sewer systems). It’s likely that robust body condition (aided by rich diets in cities) helps contemporary rats better withstand environmental stresses.
III. Genetic & Physiological Differences in Super Rats vs. Run-of-the-Mill “Regular Rats”
At the core of the super rat phenomenon are genetic mutations that distinguish these rats from their ancestors. The most well-documented genetic change is in the VKORC1 gene, which encodes Vitamin K epoxide reductase – the target of warfarin and related anticoagulants. (Pelz et al., 2005)
Researchers have identified multiple independent mutations in VKORC1 that reduce rats’ sensitivity to warfarin. For example, a mutation called Tyr139Cys in brown rats’ VKORC1 gene confers warfarin resistance by altering the poison’s binding site.
These mutations arose naturally (not caused by the poison, but present by chance) and then spread because rats with them survived poison exposure.
Studies in Europe found at least 8 different VKORC1 mutations in rats and mice that lead to varying degrees of resistance. This means “super rats” are not a single lineage, but rather a convergent phenomenon – in different places, different mutations achieved the same result of thwarting anticoagulants.
Beyond VKORC1, researchers are examining if other genes have changed. There is evidence that some resistant rats have compensatory adaptations in blood clotting and liver function.
For instance, a resistant rat might produce more of certain clotting factors or have gut microbes that synthesize extra vitamin K to overcome the poison’s effect. Warfarin works by causing fatal internal bleeding, but resistant rats manage to maintain blood clotting despite ingesting the poison.
However, these genetic advantages can come with trade-offs. Warfarin-resistant rats often have a slight fitness cost in the absence of poison – their modified VKOR enzyme is less efficient, so they require more vitamin K from the diet to stay healthy.
In natural settings like farms with low vitamin K in grain, resistant rats grew more slowly or had lower survival if poison wasn’t present, due to this metabolic handicap. But in cities, where diverse food waste provides ample nutrients, this cost is easily offset.
Essentially, modern city rats have genetically re-tuned physiology: their livers detoxify certain poisons faster, and their blood clotting pathways are less affected by anticoagulants.
Behavioral differences, while not “genetic” in a simple way, are also heritable to some extent (through a combination of genetics and learned culture). Urban super rats are more bold in exploiting new resources yet more cautious of new dangers.
Experiments have shown that offspring of trap-shy rats also tend to be more wary, suggesting a genetic component to boldness vs. caution. Additionally, scientists conducting genome sequencing on New York City rats found evidence of selection in genes related to diet and toxin metabolism, implying that city rats are evolving specialized traits for urban living. (Harpak et al., 2020)
This could include better processing of human food (rich in carbohydrates and fats) or tolerance to chemicals in sewage.
In terms of physiology, super rats often have remarkable endurance. They can survive on contaminated foods, withstand dehydration longer by finding water in drains, and have strong immune systems to cope with pathogens.
City health officials note that rats can carry at least 60 different diseases transmissible to humans, yet the rats themselves rarely succumb to many of these pathogens.
That suggests they have developed immunological resilience, living in bacteria-rich environments (like garbage dumps and sewers) with less ill effect. This hardiness is partly inherent to the species, but the individuals thriving today may be those with stronger disease resistance.
Modern super rats differ from traditional rats at the molecular level (mutated genes for poison resistance), at the physiological level (enhanced detox and nutrient use), and at the behavioral level (savvy avoidance of risks). They are, in a real sense, an evolved urban variant of the rats that populated cities a century ago – one better suited to survive our attempts to kill them.
IV. Cities & Countries Under the Most Pressure
Around the world, many urban centers are grappling with exploding rat populations and the challenges of super rats. Below is a ranked list of some of the cities and regions facing the strongest impacts.
Mumbai, India – A Never-Ending Battle: Mumbai’s dense population and vast informal settlements make it highly vulnerable to rats. One sensational report in 2012 estimated an astounding 88 million rats in Greater Mumbai. While the exact number is hard to verify, the city’s pest control department indeed destroys hundreds of thousands of rats annually (over 300,000 rats killed per year by official counts in the 2010s). Mumbai’s “night rat killers,” a crew of pest workers who patrol after dark with sticks, are almost legendary. Despite these efforts, the city faces periodic leptospirosis outbreaks (spread by rat urine) and infrastructure damage from rodents gnawing cables. The problem is compounded by heavy monsoon rains driving rats from sewers into homes. Mumbai exemplifies the struggle in many developing cities where rapid urbanization and sanitation challenges have led to explosive rodent populations.
London, UK – “Rat Capital of Europe”: London has seen rat numbers soar in recent decades, with estimates of nearly 20 million rats in the city. This would mean rats outnumber humans in London by roughly 2:1. Pest surveys indicate London’s rodents include poison-resistant strains, leading British media to frequently warn of “super rats” in the capital. The problem is exacerbated by the dense urban environment, old sewer systems, and abundant restaurant waste. London authorities have invested in control programs, but boroughs report persistent infestations, especially in older neighborhoods. The city’s sheer size and complexity give rats endless hiding places. (Other UK cities are also affected – e.g. Birmingham, Leeds, Glasgow each host over 1 million rats – but London is in a league of its own.) (STV UK)
New York City, USA – The Big Apple’s Big Rats: Famed for its rat population, New York has long battled rodents in subways and streets. While the folk myth of “one rat per person” (8+ million) is an overestimate, a statistical study in 2014 put the number around 2 million rats in NYC. These rats are increasingly immune to old poisons – one New York study found multiple colonies carrying genes for warfarin resistance. Complaints have surged: in 2022 there were 35,000 rat sightings reported to the city hotline. Infestations are worst in areas with heavy garbage output (Manhattan alleys, Brooklyn streets with packed trash bags). New York’s rats are notorious for their size and brazenness – “pizza rat” dragging a slice down subway stairs became a viral symbol. The city is under pressure as rats have adapted to thrive in its 24/7 urban ecosystem. (Rats in NYC)
Paris, France – The City of Lights…and Rats: Paris too is experiencing a rat boom. Estimates suggest ~6 million rats in Paris (roughly 1.75 rats per resident) living under the streets and along the Seine. The city’s distinctive old sewer network is an ideal rat highway. In recent years, Parisian rats have become bolder – post-pandemic, sightings of rats in broad daylight picnicking on leftover food in parks became common. Paris has had to close some parks temporarily for rodent control. The issue gained international attention as the city prepared for the 2024 Olympics, prompting intensified efforts to keep rats “underground” and out of sight of visitors. Paris officials spend about €1.5 million annually on rodent control measures, but they have also controversially discussed a more tolerant approach (“learning to live with rats”) due to the difficulty of eradication. (Fortune, 2024)
Chicago, USA – America’s Rattiest City: Chicago has earned the unwelcome title of the “rattiest city” in the U.S. for several years running, according to pest control indices. While exact population figures are not available, the city’s high ranking is based on the volume of infestations reported. In 2022 Chicago logged over 50,000 rat complaints to the 311 service line. Infestations are especially bad in alleyways and around refuse bins in residential areas. Factors like an extensive alley network (where trash dumpsters provide food) and aging infrastructure contribute. Chicago’s rats have forced innovative responses – for example, a program deploying feral cats (“Cats at Work”) to deter rats in some neighborhoods. The pressure in Chicago illustrates that even outside of the oldest coastal cities, modern metros with poor waste containment can become veritable rat havens. Other U.S. cities like Los Angeles, Washington D.C., and San Francisco also consistently rank high for rodent issues, showing the breadth of the problem. (Orkin, 2024)
Deshnoke, India – Temple of the Rats (Karni Mata Temple): A unique case, but worth noting, is Deshnoke in Rajasthan which is home to the Karni Mata Temple, famous for its sacred rats. Thousands of protected “holy” rats roam the temple complex, fed by devotees. While not a typical urban infestation (these rats are intentionally sustained), Deshnoke often tops lists of rat-heavy locations. It highlights how, under ideal conditions (no persecution, ample food), rat populations can grow extraordinarily dense. Deshnoke is sometimes cited in global rankings as having perhaps the highest concentration of rats per square meter, albeit in a confined area.
Other cities under pressure include Toronto, which has seen a 160%+ increase in rats over the past decade, and Tokyo, where urban rats thrive in dense neighborhoods (though rigorous public health measures keep numbers in check).
In the UK, aside from London, cities like Bristol and Cardiff have noted rising resistant rat populations, especially as some councils moved to bi-weekly trash collection (giving rats more continuous food access).
Baltimore and Boston in the U.S. have also struggled historically, inspiring documentaries like “Rat Film” about Baltimore’s rodent and social problems.
Below is a table of estimated rat populations for selected major cities and regions, illustrating the scale of infestations:
From the above, it’s clear that large, older cities tend to harbor the biggest rat populations – London, Paris, New York – but any city with dense population and poor waste handling can face a serious rat problem.
Warmer climates (Mumbai, etc.) in countries with poor sanitation allow rats to breed year-round, potentially yielding extraordinary numbers.
In all these places, the presence of “super rats” (poison-resistant individuals) makes control particularly challenging, as traditional poisoning campaigns yield disappointing results.
V. Global Rat Population & Environmental Factors
Globally, the rat population is often said to rival the human population. While exact global counts are impossible, some experts have ventured estimates.
A frequently cited figure is that rats and mice destroy over 42 million tons of food worldwide each year, which in the 1980s was valued around $30 billion – a proxy for their huge numbers and impact. (Almeida et al., 2013)
With the human population now in the billions mostly living in urban areas, the global commensal rat population (rats living in close association with people) could easily be in the billions as well. Factors influencing these populations include:
Climate: Warmer temperatures allow longer breeding seasons. A recent multi-city study found that cities with faster warming (milder winters) had the largest increases in rat sightings. For example, traditionally cold cities like Toronto and Chicago saw rat numbers spike when recent winters were milder than usual. Cold used to act as a natural control by killing off weaker rats each year; that buffer is shrinking.
Urban Density and Infrastructure: Crowded neighborhoods with old infrastructure (brick buildings full of gaps, old subways and sewers) provide ideal habitats. Cities with extensive subway systems (New York, London, Paris) essentially have a second layer of habitat underground where rats can multiply relatively undisturbed. Abandoned buildings or vacant lots overgrown with vegetation also become breeding grounds if not maintained.
Waste Management Practices: Perhaps the biggest factor is how a city handles its garbage. Where trash is left accessible (plastic bags on the curb, overflowing dumpsters), rats have unlimited food. New York’s practice of putting garbage bags on sidewalks overnight feeds millions of rodents nightly. In contrast, cities that invested in sealed, rat-proof trash containers or frequent trash removal have seen reductions. Any lapse – such as sanitation workers’ strikes or cutbacks in collection – often leads to a surge in rat activity within weeks.
Public Behavior: The rise of outdoor dining and casual littering can inadvertently support rat populations. Paris officials partly blamed increasing street dining and picnic culture for boosting rat food supply. Similarly, in tourist areas, overflowing bins or people feeding pigeons (and unintentionally rats) contribute to the problem. During COVID-19 lockdowns, some city centers experienced both declines (restaurants closed, less food waste) and surges (rats migrating into the open searching for food, or breeding in quiet buildings). Notably, in the UK the pandemic lockdowns led to rats moving from city centers into residential areas and suburban homes, searching for new food sources – demonstrating their adaptability.
In modeling rat populations, ecologists often use the concept of carrying capacity – how many rats a given environment can support. For a resource-rich city environment, the carrying capacity is very high. Unless aggressively controlled, rat populations tend to grow until limited by food, space, or disease. Because super rats evade many control measures, some cities are arguably nearing the true carrying capacities of their environments for the first time, which is why we see scenes of rats “spilling over” into public view.
VI. Scientific Evidence & Studies on Super Rats
A robust body of scientific research underpins our understanding of super rats. Key evidence comes from genetics, toxicology, and ecology studies:
Genetic Confirmation of Resistance: In 2005, a landmark genetic study pinpointed mutations in the VKORC1 gene of wild rats that explain warfarin resistance. This study, published in Genetics, identified multiple variants in resistant rats across Europe. Follow-up research has since found similar mutations in rats in Asia and North America. The convergence of findings is clear: warfarin resistance has a genetic basis, and those genes are spreading. Laboratory tests where wild “super rats” are given warfarin show they survive doses that kill normal rats, directly linking the genotype to the super-rat phenotype. (Chua et al., 2022) (Damin-Pernik, et al., 2022)
Rodenticide Resistance Mapping: In the UK, the Rodenticide Resistance Mapping Project led by Reading and Huddersfield University scientists has gathered DNA from rat populations to map where resistance genes occur. Preliminary results showed high concentrations of resistance in Wales, the West Country, and central southern England. This scientific approach guides pest control policy (e.g., where stronger poisons are authorized). Similar mapping in France and Germany has also been done, revealing a patchwork of resistant enclaves. For instance, a 2019 French study found resistant rats in the Paris region carried a novel VKORC1 mutation not seen in UK rats – evidence of independent evolutionary events leading to the same outcome.
Urban Ecology Studies: Ecologists have been studying how rats use urban space and how populations grow. A recent study in Science Advances (Richardson et al., 2025) analyzed rat complaint data from 16 cities and confirmed that 11 cities had significant upward trends in rat reports over the past decade. Notably, Washington D.C. saw a 390% increase in rats, and New York over 160%. The correlation with warming temperatures was highlighted, suggesting climate change is compounding the rat issue. This type of study lends scientific weight to what might otherwise be dismissed as “anecdotal” increases – it’s quantifiable and real.
Behavioral Research: There have been controlled experiments on rat behavior relevant to super rats. For example, researchers have studied bait aversion by offering rats bait that causes mild illness; unsurprisingly, the rats quickly learn to avoid that flavor. This underlies why anticoagulants were designed to be slow-acting – if a rat doesn’t immediately feel sick, it won’t associate the illness with the bait. A classic study from the mid-20th century by Curt Richter (Johns Hopkins) showed that rats can detect certain poisons (like a bitter taste of strychnine) and will refuse to ingest lethal amounts. Modern descendants of those lab rats – the wild super rats – continue to showcase these survival behaviors in real city environments. (Project Muse)
Toxicology Reports: Another line of evidence is finding poison residues in predators and in rat carcasses. In areas with heavy poison use, autopsies of rats often find sub-lethal levels of multiple rodenticides in their liver – meaning they consumed the poisons and survived. Studies across various cities have found widespread exposure of rats to anticoagulants (almost all samples had some) even though the population persists. This chemical evidence reinforces the notion that many rats are eating poison but not dying. Unfortunately, it also means predators like hawks or owls that eat those rats can accumulate the toxins (secondary poisoning), which is a serious environmental side-effect. (Murray & Sanchez, 2021)
All these studies from fields of genetics, ecology, and toxicology collectively confirm that super rats are not a myth or mere scaremongering – they are a demonstrable outcome of evolutionary pressure in urban environments. The scientific consensus is that human actions (poisoning, urbanization, climate change) are driving rapid evolutionary changes in rats, an example of “fast forward” evolution observable within a human lifetime. Ongoing research continues to monitor these trends, and scientific findings are informing new strategies to manage rodent populations.
VII. Documentaries & Media Coverage of Super Rats
Public fascination (and horror) with super rats has led to numerous documentaries and media reports worldwide.
These serve to illustrate the scope of the problem and often include gripping real-life footage. Some notable examples are below. You may be able to find many of these on YouTube if interested.
“Rats” (2016) by Morgan Spurlock: This documentary film, inspired by Robert Sullivan’s book Rats, takes viewers on a global journey through rat-infested cities. It features scenes in New York’s subway tunnels, rice paddies in Cambodia (where rats are caught for food), and research labs dissecting urban rats. The film underscores how adaptable rats are and includes interviews with scientists like Dr. Bobby Corrigan, a leading urban rodentologist. Rats is sometimes described as a horror-documentary, as it doesn’t shy away from the gruesome aspects of infestations. It vividly shows gigantic trash piles teeming with rodents and the difficulty of eradicating them.
“Rise of the Super Rats” (ITV, 2014): A British TV special that focused on the UK’s rat resistance problem. It highlighted towns like Swindon and Bristol, where pest controllers reported standard poisons no longer working. The program included genetic experts explaining the mutations in layman’s terms, and journalists accompanying exterminators on night hunts. It brought the term “super rat” into popular usage in Britain and even showed dramatic sequences of terriers and air rifles being used when poisons failed. Clips from this show often appear in news segments about UK rat infestations.
PBS: “How NYC Became a Rat Kingdom” (2024): Evolutionary biologist Shane Campbell-Staton is in this episode of “Human Footprint” that discusses the impact of humans on the planet. This episode focuses on the rats roaming NYC and how the city turned into a rat paradise.
DW Documentary “Urban Rats – The Unknown Residents of the Underworld” (2024): A German-produced documentary (available on YouTube via Deutsche Welle) that explores how rats live invisibly alongside us. It delves into scientific research projects, such as tagging rats with RFID chips to track their movements under a city. It also features Paris’s sewer museum and interviews with New York’s rodent task force. The tone is informative, showing both the problems caused by rats and the ecology of rats as urban wildlife. The title hints at an important point: much of rats’ world is literally underground and unknown to the public.
VICE (2018): “The Invicible ‘Super Rats’ Genetically Resistant to Poison”: On an episode of “Pest Kingdom” VICE Japan sat down with a handful of experts studying “super rats” to hear exactly how the rodents got so strong and find out what can be done to get them under control.
“Rat Film” (2017): A critically acclaimed documentary set in Baltimore, USA, which uses the city’s rat issue as a lens to examine historical segregation and urban poverty. While not about “super rats” per se, it provides context on how socio-economic factors and infrastructure neglect contribute to infestations. It’s a more experimental film but has become part of the conversation on urban rats by illustrating that where you have decay and inequality, rats thrive.
News Features: Countless news programs have run segments on super rats. For instance, National Geographic and the Discovery Channel have done specials on giant sewer rats and resistant rats. A memorable NG article titled “Climate change is amazing—if you’re a rat” (2020) described how warming cities are a boon for rodent survival. Another viral story was the New York Times piece on Chicago’s feral cats being used for rat control, showing creative measures taken in top-infested cities. Television news often accompanies city pest crews at night – green night-vision footage of rats scuttling in hordes, which drives home the scale (for example, a BBC segment once showed a heap of grain in a barn seeming to pulsate from the number of rats burrowing in it).
YouTube & Social Media: Many clips circulate online, like the “MonsterQuest” episode Mutant Super Rats (History Channel), which speculated (a bit fantastically) about whether rats could grow larger in the future. YouTube videos from pest control channels also show things like colonies of “mega rats” found in neglected properties, or tests of new trap gadgets. These media collectively shape public perception, making “super rats” a part of pop culture discussions around city life.
Through documentaries and media, the public has been shown that this is not just an isolated local issue but a global trend. Seeing footage from different countries underscores that super rats are everywhere – lurking in subways, alleys, landfills, even restaurants (some videos have captured rats boldly running across the floor of fast-food outlets at night). While often alarming, this media attention has also increased political will to address the problem, as no city wants to be known primarily for its rats.
VIII. Countermeasures: Fighting Back Against Super Rats
Confronted with ever more resilient rats, researchers and city officials are developing a multifaceted arsenal of countermeasures. These range from high-tech genetic interventions to old-fashioned sanitation improvements. Here we analyze the key strategies:
Next-Generation Poisons: With many rats now surviving first-generation anticoagulants (Mutant Rats Resist Warfarin), pest control companies have turned to stronger poisons and different active ingredients. Second-generation anticoagulants (SGARs) like brodifacoum, flocoumafen, and difethialone are more potent and can kill resistant rats. They are effective even against “super rats” in many cases, but they come with a risk of poisoning non-target wildlife and are regulated (often requiring special permits for outdoor use). Aside from SGARs, entirely different classes of rodenticides are being used: for example, bromethalin (a neurotoxin) and cholecalciferol (Vitamin D3) baits cause calcification or nervous system failure in rodents and kill them within days. Rats have no natural resistance to these yet. Some products even mix multiple modes of action (e.g., an acute poison with an anticoagulant) to overcome any single resistance. The development of poisons is essentially an ongoing chemical arms race – whenever a new toxin is deployed, there’s pressure on rats to evolve counter-resistance, so rotation and careful use of poisons is recommended by experts to slow resistance buildup. (The Battle Against Super Rats)
Improved Baiting Strategies: Instead of simply laying poison, pest professionals now employ smarter strategies. Pre-baiting is one: offering non-poisonous food first to gain the rats’ trust, then switching to poison bait once they’re confidently feeding. This addresses neophobia. Encapsulated baits and flavor-masking are also used to prevent rats from tasting the active ingredient. Some companies use attractants that are irresistible even to cautious rats (like blending poison with foods high in fat and sugar, which rats crave). Additionally, tracking powders (poison that sticks to rats’ fur and is ingested during grooming) can hit rats that won’t eat bait. These measures acknowledge rat intelligence and work around it.
Fertility Control (ContraPest Birth Control): A breakthrough alternative approach is controlling rat reproduction rather than trying to kill every rat. One example is ContraPest, an EPA-approved liquid contraceptive bait for rats. Rats that consume ContraPest experience temporary infertility – the product induces a kind of menopause in female rats and lowers sperm counts in males. Field trials have shown promising results: in one Washington D.C. pilot, rat activity dropped by 90% when fertility control was deployed, although results were inconclusive longer-term. Another trial in Seattle reported noticeable declines in rat populations using ContraPest. The advantage of fertility control is that it’s humane and species-specific (it doesn’t harm predators or other animals) and it tackles the root cause of population explosions. The downside is cost and speed – it may take months for a colony to diminish as older rats die off naturally and no new pups are born. Some cities are now combining fertility control with traditional methods; for example, New York City’s transit authority has experimented with using ContraPest in subway stations. This method, still emerging, could become a crucial tool to outsmart super rats by simply stopping their reproductive cycle.
Gene Editing & Gene Drives: Looking further into the future, scientists have proposed using advanced genetics to control rats. A gene drive powered by CRISPR/Cas9 gene editing could theoretically spread a deleterious gene through a rat population – for instance, a gene causing all offspring to be male (thus eventually crashing the population for lack of breeding females). (Manser et al., 2019) This has been successfully modeled in lab mice and some insects. The potential of a CRISPR gene drive is that a small release of genetically modified rats could lead to self-disseminating population control. However, this approach is fraught with ethical and ecological concerns: what if the gene drive spread beyond the target city or jumped to wild ecosystems? Work is ongoing to make gene drives controllable and limited. Another genetic approach would be to re-sensitize rats to warfarin – theoretically editing the VKORC1 gene back to a non-resistant form or inserting a vulnerability. But delivering such genetic changes to millions of wild rats is a formidable challenge. At present, gene editing for pest control is mostly in research phase (tested in contained island environments, for example). It might become viable in coming decades, especially for closed systems like islands or subway systems where escape is minimal. If deployed carefully, gene drives could be the silver bullet against super rats, making them effectively engineer their own demise by breeding in a lethal trait.
Environmental & Ecological Controls: This category includes leveraging natural predators and modifying habitats. Some cities encourage predators like owls, hawks, or feral cats to help keep rats in check. For instance, installing owl nesting boxes in parks can attract owls that consume many rodents nightly. However, predators alone rarely suffice in core urban areas (cats, for example, may kill some rats but tend to go after easier prey like mice, and they can’t enter deep rat burrows). Another approach is biological control via diseases or parasites that target rats. Historically, poisons derived from infections (like salmonella) were attempted to spread in rat populations, but these pose risks and have fallen out of favor. On the ecological side, disrupting rat habitats is key. This means sealing building cracks, installing rat guards on sewer pipes (one-way valves that stop rats from climbing up toilets), and digging barriers into foundations. Modern building codes in some cities now mandate rat-proofing measures for new construction. Urban planners also aim to reduce the availability of derelict spaces – for example, ensuring old tunnels or abandoned lots are sealed or developed so they don’t become rat harborage. Community clean-up programs (removing rubble, trimming overgrown vegetation in which rats hide) are a simple but effective tool to make areas less rat-friendly.
Smart Technology & Monitoring: In the digital age, tech is being brought to bear on rodent control. Smart traps are devices that detect and kill rats automatically and send an alert when a kill is made. Some can reset themselves after a kill (e.g., CO₂-powered captive bolt traps that can dispatch multiple rats before needing service). Cities like Washington D.C. have trialed smart bins that detect rodent activity. Remote sensing is used to identify burrows – for example, using thermal imaging drones to spot colonies in dense shrubbery or using motion-sensor cameras in subway tunnels to map rat highways. Data-driven approaches, like New York City’s “rat information portal,” map complaints and infestations to target interventions better. Chicago’s analytics team even used algorithms to predict which neighborhoods were at risk of rat outbreaks based on factors like garbage 311 calls and building violations. By predicting and preventing rather than just reacting, cities hope to stay one step ahead of the rodent population curve. (East Coast Cities are Zapping Rats with High-Tech Traps)
Public Health & Sanitation Measures: Ultimately, the most sustainable solution is reducing the factors that let rats thrive. This means strict sanitation: frequent trash collection, rat-proof trash cans (sturdy containers with lids that rats can’t chew through – metal or heavy plastic with no drain holes that rats could enter). Some cities, like New York currently, are piloting “containerized waste” in sealed curbside bins instead of bags on the street, aiming to starve rats out of their neighborhoods. Legislation can help too; for instance, fines for dumping garbage illegally or requirements for restaurants to have locked trash storage. Public education is important: teaching communities not to litter, to secure compost bins, and not to feed wildlife (pigeons, feral cats, etc., because leftover food feeds rats). In many cities, health departments run campaigns on how to “rat-proof” your home – sealing holes as small as a quarter (rats can squeeze through incredibly small openings), and eliminating standing water where rats could drink. Some places have instituted “rat czars” or dedicated rodent control officers to coordinate these efforts (New York City famously appointed a Rat Czar in 2023 with a mandate to unify the city’s approach). These measures may lack the sci-fi appeal of gene editing, but experts emphasize that denying rats food and shelter is the foundation of any control strategy. Super rats may resist poison, but they still need garbage to eat – cut off the garbage, and even super rats will decline.
It’s increasingly clear that no single method will solve the super rat problem. Integrated Pest Management (IPM) is the buzzword: combining chemical, biological, structural, and educational tools. For example, a city might do the following in a worst-hit area: fix sewer cracks and install rat barriers, deploy ContraPest for a year to sterilize the population, trap aggressively to cull numbers, and push a neighborhood garbage cleanup program – all at once. Such concerted efforts are costly but have shown success in small-scale trials. The war on super rats is prompting human innovation at every level, essentially forcing us to become smarter and more adaptive, just as the rats have.
IX. Estimated Economic (Financial) & Societal Impact of Super Rats
The proliferation of super rats is not just a nuisance – it carries significant economic costs and societal consequences. From infrastructure damage to disease control and quality of life, the impact is far-reaching. (Diagne et al., 2023)
Economic Damage: Globally, rats cause billions of dollars in damage each year by gnawing on wiring, infiltrating buildings, and contaminating food. In the United States alone, rodents are estimated to cost the economy around $19 billion per year in damage and control expenses. This figure (from a USDA/CDC analysis) includes things like structural fires from rats chewing electrical wires, losses of food in warehouses, and expenses of pest control operations. For example, rats in New York have been known to chew through fiber-optic cables, disrupting internet service – an economic hit in a knowledge economy. In agriculture, rats in grain silos or rice storage can destroy enormous quantities of food (harking back to that 42 million tons figure). Developing countries face major food security challenges when rodent outbreaks occur; a rat infestation in a village’s rice stores can ruin harvests and lead to hunger. (Parsons, 2023)
Municipal Costs: City governments spend large sums on rodent control and remediation. New York City’s latest initiative earmarked $3.5 million in a single fiscal year to ramp up rat mitigation in targeted “Rat Reduction Zones”. (City Rat Czars) Under Mayor Bill de Blasio, NYC also launched a $32 million multi-agency plan in 2017 to curb rats by 70% in key areas. Paris spends €1.5 million annually as noted, and has crews conducting over 7,000 interventions a year. London’s boroughs collectively spend millions of pounds on pest control operations (one estimate put it at £6–7 million per year across the city). These are direct costs – indirect costs include things like cleaning up after rats (power-washing sidewalks to remove droppings) or repairing gnawed infrastructure. Over 40–50 years, invasive rats and mice have cost the UK economy over £80 million in direct damages and control measures. Add to that the prevention costs that never stop (every year, budgets must account for continued vigilance). (CABI.org, 2023)
Public Health: Society bears the burden of diseases spread by rats. Although modern sanitation prevents catastrophes like the Black Plague in most places, there are still substantial health impacts. Rats are vectors for leptospirosis (Weil’s disease), salmonellosis, hantavirus, and others. Outbreaks of leptospirosis have occurred in urban slums and even in cities like New York (in 2017 a cluster in the Bronx was traced to rat urine). Treating these illnesses and conducting epidemiological investigations is costly for health departments. There’s also a mental health aspect: living with a severe rat infestation can cause stress, anxiety, and sleep disturbances for residents (imagine hearing rats scurrying in your walls nightly). In some lower-income neighborhoods, people have reported being afraid to let children play on the floor due to rat urine contamination or even rats biting babies (rare but reported). This leads to intangible costs in quality of life.
Property Values & Business Impact: A neighborhood known to be rat-infested can see property values stagnate. Small businesses like restaurants suffer reputational damage if rats are seen – a single viral video of a rat inside a bakery can cause huge losses and shutdowns for extermination. Pest infestations in commercial settings can lead to health department closures, again hitting revenue. A study in the UK found that pest infestations (mostly rodents) cost businesses £1.2 billion in lost revenue and productivity per year, due to closures and damaged goods. For homeowners, discovering rats often means paying for exterminators, sealing services, and even tearing out and replacing insulation or wires – a financial hit to individual families.
Infrastructure Resilience: On a macro scale, rats can undermine infrastructure by burrowing. There have been instances of road collapses or cave-ins attributed in part to rat tunnels weakening the soil. In Washington D.C., rats burrowing under sidewalks have caused sections to sag. Sewer systems also take a hit: fatbergs (congealed grease blockages) in sewers are sometimes exacerbated by rats nesting around them. Cities then incur extra maintenance costs to inspect and repair these systems. Railways and power stations also allocate budgets to rodent-proof critical cables and equipment, especially after learning the hard way (for example, a partial power outage in Manhattan in 2020 was suspected to be due to a rat shorting a transformer).
Societal Perceptions & Inequities: There’s an important societal dimension in that rat infestations often highlight inequalities. Typically, poorer districts have more severe rat problems in part due to older housing and less effective waste removal – this was famously documented in Baltimore, where predominantly Black neighborhoods had both high rat density and a history of underinvestment (the documentary Rat Film explores this). The cost of rats is thus not evenly distributed: vulnerable communities may spend a higher proportion of their income dealing with rats or suffer more from the associated health issues. Some of this is also due to the people living there who are less responsible overall — littering, leaving trash unsecured, etc. (it’s a bidirectional relationship). In cities like Paris and New York, mayors have had to respond to citizen outcry that some areas (usually wealthier tourist zones) get prompt rat control, while others are neglected — but some of this is the wealthy citizens themselves spending more on controlling rats and taking more initiative.
To put the financial impact in perspective, consider that the global invasive rodent cost reported (likely underestimating) was $3.6 billion from 1930–2022 in recorded damages. The true global cost each year now is certainly much higher – some have speculated it could be in the tens of billions annually when factoring in all sectors (agriculture, health, cities).
These costs mount year after year, essentially a tax on society for living with these pests. On the flip side, the “rat economy” – i.e., the pest control industry – is a multi-billion dollar sector worldwide, as demand for rodent control services stays high. Cities like New York, Chicago, and Paris now see rodent management as critical to their economic vitality, since an overwhelmed city can deter tourism and investment.
Super rats exert a financial drag and social strain on communities. They eat our food, force us to repair and reinforce our structures, demand continuous spending on control, and can even fray the social fabric (causing blame games between neighborhoods or political leaders when infestations get out of hand). The fight against these rodents is as much about protecting our economies and public health as it is about convenience or aesthetics.
X. Future Outlook of Super Rats (2025)
What does the future hold in the age-old war between humans and rats, now that the rats have gained an evolutionary upper hand? We can project several potential scenarios.
Continued Evolutionary Arms Race: If current trends persist, rats will keep evolving in response to our control efforts. We invent a new poison; within years, selective pressure will produce rats that can resist it. We deploy traps en masse; the most trap-averse rats will survive and breed. This suggests a future where rats become increasingly impervious to chemical control. It’s conceivable that decades from now, urban rats could carry multiple resistance genes – not just to anticoagulants, but maybe to different classes of toxins – making them virtually unkillable by conventional poisons. They may also become more behaviorally savvy, as each round of culling by traps removes the more gullible individuals. In evolutionary terms, we are “training” the rat population to be smarter and tougher. This arms race could reach a point of stalemate, where poisoning is largely ineffective and we are forced to rely on non-lethal controls (like exclusion and starvation methods). Some scientists have even joked that we might eventually have “super-super rats” that are the size of small dogs and can digest almost anything – an exaggeration, but it highlights that there is no clear cap on adaptive potential when selection is strong and generation times are short.
Population Explosion vs. Plateau: In many cities, rat populations are likely to continue rising in the near term, especially under favorable conditions (warming climate, urban growth, strained sanitation systems). We could see scenarios like mega-infestations in certain areas – think of monumental heaps of garbage in a megacity literally teeming with rats, to the point where daily life is affected (e.g., rats swarming subway platforms every night, or parks unusable due to burrows). However, there are natural limits. Rats still need food and space. First principles of population ecology dictate that any population will plateau at carrying capacity. We might witness more frequent crashes as well: if a population overshoots (too many rats, not enough food), disease outbreaks among rats (like salmonellosis or rat epidemics of viruses) could knock the numbers down temporarily. Also, social stress can limit super high densities – extremely crowded rat colonies can experience infighting, cannibalism, and lower fertility. So while the trajectory is upward, it won’t be exponential forever in a given locale; it will level off and fluctuate. The worry is that the plateau level in many cities might be far higher than what we have tolerated in the past. The “new normal” could be a constant background of rats that we simply manage around.
Technological Game-Changer: On the optimistic side, a new technology might decisively shift the balance back in our favor. For instance, if gene-drive solutions become practical, we could in theory eradicate local rat populations by causing a genetic crash (as has been done with mosquitoes in some trials). If, say, by 2035 a carefully tested CRISPR gene drive is available that only affects the city’s rats and is reversible or stops at city limits, it could be deployed in major cities. We might see some cities becoming essentially rat-free (imagine a “Rat Zero” campaign analogous to smallpox eradication). Another possible game-changer is improved urban infrastructure: if cities manage to redesign waste systems (underground container systems, automated vacuum trash disposal like in some modern developments), the carrying capacity for rats would plummet. They simply wouldn’t find enough food to sustain huge numbers, causing a population collapse. It requires large investment, but some future cities (or renovated sections of cities) might achieve a state where rats are rare because the environment doesn’t support them. In this scenario, super rats could be a temporary problem of the 20th–21st centuries that we eventually engineered away by denying them sustenance and access.
Worst-Case Scenarios: In a more dystopian extrapolation, one could imagine that super rats, if unchecked, contribute to serious crises. For example, if climate change leads to more frequent floods in coastal cities, those floods could flush thousands of sewer rats into the open, potentially spreading diseases to disaster-stressed human populations. There’s a scenario where a novel pathogen carried by rats jumps to humans (somewhat like how SARS-CoV-2 came from wildlife) – crowded rats are reservoirs of many viruses, and increased contact with people could increase zoonotic risk. Economically, if rats severely damage key infrastructure (imagine coordinated outages or even a grid failure triggered by multiple cable gnawings, or a port’s grain silos compromised by rat contamination leading to food shortages), they could amplify human crises. While rats alone likely won’t topple societies, in synergy with other stressors they could worsen situations (hence the term “secondary disaster agents” sometimes used in emergency management). The worst-case trajectory is one where rats become an unmanaged menace and essentially we surrender certain areas to them – something no city wants, but in failed-state scenarios one can find neighborhoods literally overrun.
Nature’s Balancing Act: Interestingly, if rats truly became extremely abundant, nature might introduce its own checks. Predators that were once rare in cities (hawks, owls, even coyotes) might be drawn in by the plentiful prey, establishing a new urban food web that keeps rats somewhat in balance. We already see hawks adapting to city life by preying on pigeons; they could take rats too if the pickings are easy. Alternatively, disease could keep rat populations cyclic (like how rabbit populations in Australia boom and bust due to introduced viruses). Essentially, if humans can’t fully control the super rats, other natural forces might – though that could come with its own problems (who wants a city full of coyotes just to eat the rats?).
Considering: rats breed fast, mutate fast, and exploit niches; humans innovate, organize, and can alter environments. The future will be determined by which side leverages its strengths more effectively.
If human society prioritizes rat control with the same vigor it tackles other big challenges (energy, security), we could very well see a decline of super rats via integrated strategies.
On the other hand, if urbanization outpaces our control measures, we might just have to learn to live with a higher baseline of rodent presence. Some cities are already framing it this way – Paris debating “living in harmony with rats” rather than futilely trying to eliminate them.
In a speculative far future, perhaps urban rats and humans reach a sort of equilibrium: rats kept at manageable levels through constant but efficient management, and humans accepting that zero rats is unrealistic.
Or, in a bold twist, perhaps scientists find a way to domesticate or alter rats to be less harmful – a stretch, but for instance using gene editing to make city rats less fertile long-term or even herbivorous (so they don’t scavenge our trash).
Ultimately, the super rat saga demonstrates a classic evolutionary outcome: two species (rats and humans) influencing each other’s evolution in a perpetual dance. As long as we have sprawling cities and generate waste, rats will be there, adapting to whatever we throw at them.
The hope is that through science, vigilance, and smarter urban design, we can prevent today’s super rats from becoming even more super – and perhaps tip the balance to ensure the “rat of the future” is a rarer, more benign presence in our lives rather than a menace.
My thoughts re: Super Rats…
They’re a big problem in terms of public health and costs (health & infrastructure damages). Not much progress has been made in reducing rat populations in large U.S. cities — and in places like India there’s almost zero hope with the pollution and unsanitary conditions/behaviors (endless trash & human shit everywhere). The rats keep evolving and becoming extra super.
How Rat-Related Costs Are Measured:
Rat-related economic impacts are usually calculated through several key categories:
Healthcare Costs: Treatment for rodent-borne diseases (leptospirosis, hantavirus, salmonella). Public health interventions and sanitation programs. Reliable data obtained through public health department reports, CDC surveillance, and epidemiological studies.
Property & Infrastructure Damage: Repairs for damage to electrical wiring, plumbing, structural components. Assessed by insurance claims, municipal maintenance budgets, and building management reports. Highly reliable at individual levels but varies significantly between cities.
Business & Economic Impacts: Costs related to restaurant closures, fines, lost revenues, decreased tourism, and property value depreciation. Calculated from city economic reports, insurance data, tourism industry metrics, and local business associations. Less precise due to variability in indirect economic impacts.
Pest Control Costs: Direct expenditures on pest management. Highly accurate, directly measurable from municipal contracts and private pest control industry data.
Realistic Cost Estimates:
Real-world studies from credible sources generally agree that rat infestations in large cities incur high costs, but exact numbers vary:
New York City: Official estimates (including healthcare, sanitation, and control efforts) consistently exceed $30–$50 million/year. Broader economic impact estimates (including infrastructure, businesses, lost tourism) easily surpass $150 million/year.
Chicago, Los Angeles, Other Metros: Comparable estimates place total impacts in the range of $50–$200 million annually per large metro area, depending on infestation severity.
Reliability of Measurements:
Direct costs (healthcare, pest control, property repairs) are typically highly reliable because they're tangible, documented, and tracked by municipalities and private businesses.
Indirect costs (economic losses, decreased tourism, property values) can be less precise and often extrapolated from broad economic studies, surveys, and statistical models.
Conservative Realistic Estimate:
A more conservative yet widely accepted estimate is:
Direct measurable costs per 1M population city: $30M–$50M/year
Including broader indirect economic impacts: realistically approaches $100M–$150M/year.
Even using conservative numbers, this eradication plan (initial investment ~$65M, ~$9M annual maintenance for 1M residents) remains highly cost-effective, paying for itself within approximately 1-2 years.
Bottom Line: While exact figures vary and indirect costs carry uncertainty, even conservative estimates show that urban rats are extremely costly. This aggressive protocol remains financially beneficial and justified—even at lower-end cost scenarios.
This is something that needs to be seriously addressed. It’s costing cities and people a lot of money.
A good first step is education, but a strategy that combines things like: smart traps, next-gen rodenticides, fertility control (ContraPest), robot CO2 systems, infrastructure/seal-up improvements & incentives, gene drive experiments, and ongoing data analysis/audits of the system (what’s working, what’s not, etc.) — can address this problem.
Savings are estimated to be ~$500k-$1M per 100,000 resident-area. Probably need to measure this better, but data collection and integration should be getting easier.
Keep going “as is” (status quo) and the “super rats” stay winning.