Where are there no rats and mice? - briefly
Highly controlled sterile environments—such as operating theaters, pharmaceutical cleanrooms, and spacecraft habitats—are kept free of rodents. Strict pest‑exclusion measures and sealed structures maintain this condition.
Where are there no rats and mice? - in detail
Rats and mice are absent in environments that lack the basic conditions required for their survival and reproduction.
Cold‑dependent regions such as the Antarctic continent and its surrounding islands provide temperatures far below the physiological limits of these rodents. The permanent subzero climate, scarcity of vegetation, and absence of permanent human settlements prevent establishment of any rodent populations.
High‑altitude deserts, for example the Atacama Plateau and the Tibetan Plateau, combine extreme aridity with thin air and low ambient temperatures. Soil moisture is insufficient to support the insects and seeds that form the primary diet of small rodents, resulting in a natural barrier to colonisation.
Man‑made sterile zones are deliberately designed to exclude all fauna. Clean‑room facilities for semiconductor manufacturing, pharmaceutical production, and aerospace assembly maintain positive air pressure, HEPA filtration, and rigorous decontamination protocols. These measures eliminate any chance of rodent ingress.
Isolated islands with stringent biosecurity policies, such as certain Pacific islands (e.g., the Galápagos and some New Caledonian reserves), enforce quarantine procedures that have kept rodent species out. Continuous monitoring, cargo inspection, and rapid response to incursions maintain the rodent‑free status.
Submerged habitats, including deep‑sea research stations and underwater habitats, present an environment devoid of oxygenated air and suitable food sources. The pressure and lack of terrestrial vegetation make survival impossible for any terrestrial rodent.
Extreme saline environments, such as hypersaline lakes (e.g., the Great Salt Lake) and salt flats, contain water chemistry that is toxic to mammals. The high osmotic pressure prevents rodents from drinking or obtaining moisture, leading to natural exclusion.
In summary, locations that combine one or more of the following factors—permanent subzero temperatures, extreme dryness, rigorous sterility controls, enforced biosecurity isolation, underwater conditions, or hypersaline chemistry—are devoid of rats and mice.