The water shrew, Sorex palustris, is one of Utah's most common shrew species. It can be found near mountain streams, lakes, and marshes throughout the state. The overall range of the species includes the northeastern United States, much of the western United States, southern Alaska, and most of Canada. As its name implies, the water shrew is an excellent swimmer and is almost always found near water.
The water shrew eats primarily aquatic insects, but terrestrial insects, spiders, other invertebrates, and even small fishes are also consumed. The species breeds throughout the spring and summer, and females can give birth to two or three litters of three to ten young each year. The water shrew is active throughout the year, primarily during the evening and early morning hours. Even when active, however, the water shrew is secretive and seldom seen by the casual observer.