During the past 35 years, the least shrew (Cryptotis parva) has expanded its distribution along riverine and other mesic corridors in western parts of its distribution, although some recently discovered populations in the West might represent relicts of a previous Pleistocene distribution. In Nebraska, the least shrew originally was known only from eastern and central parts of the state, but recent records are now available from extreme west-central Nebraska and the northwestern corner of the state. Our record from west-central Nebraska probably represents recent westward expansion of C. parua along the North Platte River. This capture in Scotts Bluff Co., Nebraska was only 225 m from the Wyoming state line. Selective trapping along the North Platte River and its tributaries in eastern Wyoming likely will result in discovery of least shrews in that state.
Geluso, Keith; White, Jeremy A.; and Bogen, Michael A., "Least Shrew (Cryptotis parva ) in Extreme West-Central Nebraska" (2004). Biology Faculty Publications. 55.