Where are the most rats in the world? - briefly
The densest rat populations occur in major metropolitan centers, notably New York City’s subway and sewer networks, which host the largest numbers worldwide. Comparable concentrations are also reported in Mumbai, Tokyo, and other densely populated Asian cities.
Where are the most rats in the world? - in detail
The global concentration of rats is highest in densely populated urban centers where food waste, water sources, and shelter are abundant. Estimates based on pest‑control reports, academic surveys, and municipal data identify the following locations as the primary hotspots:
- New York City, United States – The Metropolitan area supports an estimated 2 million Norway rats (Rattus norvegicus), with the borough of Manhattan alone accounting for roughly 300 000 individuals. Sewer systems, subway tunnels, and abundant garbage provide optimal conditions.
- Mumbai, India – Rapid urban expansion and inadequate waste management have led to a rat population exceeding 1 million, predominantly the roof‑rat (Rattus rattus). Coastal districts report the highest densities.
- Tokyo, Japan – Approximately 800 000 brown rats inhabit the metropolitan region, concentrated in the central business district and surrounding riverbanks. Seasonal spikes occur during the summer months.
- São Paulo, Brazil – Surveys indicate around 600 000 individuals, with the species composition split between Norway and roof rats. Informal settlements contribute significantly to the numbers.
- London, United Kingdom – Pest‑control agencies estimate 500 000 rats across the capital, with the highest concentrations in the Docklands and inner‑city boroughs.
Key factors driving these figures include:
- Waste generation – Cities producing over 2 kg of solid waste per capita per day provide continuous food sources.
- Infrastructure design – Underground utilities, aging sewage networks, and extensive subway systems create protected habitats.
- Climate – Temperate to subtropical climates support year‑round breeding cycles, increasing reproductive rates.
- Population density – Human densities above 10 000 inhabitants per square kilometer correlate with higher rodent counts.
Scientific studies using mark‑recapture techniques, genetic sampling, and remote‑sensing of waste sites confirm the reliability of these estimates. While exact numbers fluctuate with seasonal variations and control measures, the listed metropolitan areas consistently rank at the top of global rat abundance.