Black rats are an Old World invasive, not a native Texas mammal, and NatureServe lists them as exotic with no conservation rank assigned. The state’s 827 records cluster around three coastal refuges, Aransas, Padre Island, and Brazoria, but that says more about where boat docks, storage buildings, and visitor facilities sit than about genuine refuge habitat; black rats live around structures and stored grain wherever people are, and coastal refuges have exactly that kind of infrastructure.
Reporting peaks in April, though a commensal rodent like this is likely active year-round, and the spike more plausibly reflects when refuge staff or visitors happen to notice one than any real seasonal swing in the population. With 827 records, black rats rank in the common bucket for Texas mammal encounters, though for an invasive species that thrives around human structures statewide, that count almost certainly understates how widespread they are outside the handful of well-surveyed refuges.
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