Why did rats arrive? - briefly
Rats migrated to the area in response to plentiful food supplies and accessible shelter. Human waste production and inadequate storage practices created conditions that facilitated their movement.
Why did rats arrive? - in detail
Rats appeared in new regions primarily because humans created environments that supported their survival and reproduction.
- Trade routes introduced them aboard ships, where they found shelter in cargo holds and food stores.
- Urban expansion provided abundant refuse, warm structures, and nesting sites, allowing populations to thrive.
- Agricultural practices generated grain surpluses and storage facilities that offered constant nourishment.
Ecologically, rats exploit vacant niches left by native species that cannot compete with their rapid breeding cycle and omnivorous diet. Their adaptability to diverse climates enables colonization of temperate, tropical, and even arid zones.
Historical records show that maritime commerce in the 16th–19th centuries accelerated their spread across continents. Ships traveling between Europe, Asia, and the Americas regularly carried rats, which disembarked at ports and quickly established local colonies.
Modern transportation continues the pattern: freight containers, aircraft cargo bays, and trucking routes act as vectors, moving rodents into previously uninfested areas. Once established, rats alter local ecosystems by preying on insects, competing with small mammals, and dispersing pathogens.
In summary, the combination of human-mediated movement, urban and agricultural waste, and the species’ biological flexibility explains the widespread arrival of rats in diverse habitats.