Norway rats arrived in Massachusetts with European shipping in the 1700s, and NatureServe classifies the species as exotic here rather than assigning it a conservation rank at all. The named sites, Cape Cod National Seashore, Monomoy National Wildlife Refuge, and Parker River National Wildlife Refuge, are coastal protected areas rather than the dumpsters and building foundations where most Massachusetts rats actually live; a rat logged at a wildlife refuge is more likely denning in dune grass or a boardwalk than in open habitat.
Records carry a spring peak in April and May with a secondary bump in October, activity tied more to breeding cycles and seasonal food availability than to any change in how widespread the species is. Rats stay active through Massachusetts winters, sheltering in burrows and structures rather than truly going dormant.
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