The black rat isn’t a Massachusetts native, and the state’s record reads like the biography of an import. This is the old ship rat of the seafaring centuries, an introduced species that arrived with people and persists around buildings, warehouses, and port infrastructure. NatureServe gives it no state rank, since conservation categories don’t apply to a species that was never part of the local fauna.
The county pattern fits that seafaring reputation: both of the state’s 2 records from 2000 to 2026 come from Suffolk County, the Boston waterfront. Port cities were the entry points, and the records track human settlement more than any wild habitat.
Both records fall in September, far too few to show any seasonal pattern. Coastal refuges like those on Cape Cod and the North Shore hold similar cover, but the reports themselves come from towns and cities. This rat goes where people go.
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