Subspeciation in the Meadow Mouse, Microtus pennsylvanicus, in Wyoming, Colorado, and Adjacent Areas

This audio walks listeners through a detailed investigation of the meadow mouse, a small rodent that populates the high plains and mountain valleys of the western United States. The narrator explains how early biologists divided the species into two color‑based subspecies, but recent fieldwork revealed a more intricate pattern. By examining specimens from the Black Hills, the Big Horn Mountains, and the Colorado Front Range, the study maps subtle shifts in fur hue that hint at hidden evolutionary branches.

To sort the variation, the researcher devised a simple five‑point scale, using representative skins as benchmarks and assigning each new sample a number from pale to dark. The resulting data are plotted on a regional map, exposing a striking gradient and suggesting three previously unrecognized subspecies. Listeners will hear how statistical analysis and careful museum work combine to reshape our understanding of a seemingly modest creature, illustrating the broader process of scientific discovery.