The smoky shrew occurs throughout the Northeast from Nova Scotia to North Carolina. It inhabits most of Pennsylvania but is scarce in southwestern and southeastern counties. Coloration is a uniform dull brown, except for the bicolored tail, brown above and yellowish below, and pale buffy feet. In summer, the fur is slightly darker and browner. The smoky shrew resembles the masked shrew but is larger, stouter and darker. Overall length, 3.7 to 5 inches; tail, 1.4 to 2 inches; weight, 0.21 to 0.35 ounces, about one-third the weight of a house mouse.
The smoky shrew prefers cool, damp woods with deep leaf litter. Prime habitats include deep, shaded hemlock ravines, northern hardwood forests, spruce and sphagnum bogs, and stream borders with moss-covered boulders and logs.
Smoky shrews may be active at all hours. They burrow through the leaf mold or travel in other animals’ tunnels. They eat insects, salamanders, snails, worms, spiders and small birds either alive or as carrion.
These shrews build baseball-size nests of dry vegetation deep within rocky crevices or stone piles, or under rotting logs, stumps or boards. They breed from late March into August. Females bear up to three litters annually, of 2 to 8 (usually 5 or 6) young. Offspring are independent by one month of age.
Smoky shrews appear to be social animals, with populations fluctuating from year to year. They fall prey to short-tailed shrews, weasels, foxes, bobcats, hawks and owls. Maximum lifespan is about 17 months.