The cinereus shrew, also called the masked shrew, is one of the smallest mammals in Massachusetts, and its metabolism runs so fast it has to hunt insects and other invertebrates almost around the clock rather than settling into a clear day or night pattern. Parker River National Wildlife Refuge leads the named sites with three records, its damp, leaf-littered understory offering the cool, moist ground this shrew burrows through.
Records spike sharply in April, more than seven times the January low, likely reflecting the start of breeding-season movement as much as any change in how often people are out looking. NatureServe ranks the species S5, secure, in Massachusetts, and it’s found across nearly every wooded and wetland habitat the state offers despite rarely being seen.
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