Family: Soricidae, Shrews view all from this family

Description Very dark or black above; belly silvery white. Long tail. Hindfeet have fringe of stiff hairs. L 5 5/8–6 1/4" (144–158 mm); T 2 1/2–3 1/8" (63–78 mm); HF 3/4 – 7/8" (18–21 mm); Wt 3/8–5/8 oz (12–17 g).

Similar Species Most other long-tailed shrews are much smaller. Pacific Water Shrew is dark brown above and below; fringe of hair on hindfeet is poorly developed.

Breeding May begin breeding as early as January and continue through August. 2–3 litters per year of usually 6 young, born after 21-day gestation. Females born early in year may reproduce later the same year.

Habitat Among boulders along mountain streams, or in sphagnum moss along lakes.

Range Southeastern Alaska and most of Canada south throughout ne California, through Utah and central states to ne South Dakota, n Minnesota, Wisconsin, and Michigan; New England south through Appalachians to Nantahala Mountains of North Carolina. Isolated population in White Mountains of e Arizona.

Discussion At home in water, the Water Shrew can dive to the bottom; when it stops swimming, air trapped in the fur pops the animal back to the surface like a cork. Owing to the fringe of hairs on the hindfoot, which increases the foot’s surface area and traps air bubbles, this shrew can actually run on the water’s surface. Its velvety fur is water-resistant; if it does become wet, the shrew takes to shore and dries itself thoroughly with rapid strokes of its hindleg, with the hair fringe functioning as a comb. It eats aquatic food, such as mayfly and stonefly nymphs, as well as terrestrial invertebrates. Enemies include weasels, minks, and fish, such as pickerel, pike, bass, and large trout. Now included in this species is the Glacier Bay Water Shrew (formerly S. alaskanus), known only from Point Gustavus, Glacier Bay, Alaska.