The Baculum in the Chipmunks of Western North America

An unexpected gateway into the world of tiny mammals opens with a close‑up study of the baculum, the bony core of the male chipmunk’s penis. By examining how the shaft, tip, and keel differ among species of the subgenus Neotamias, the author shows that even the smallest skeletal details can illuminate big questions of classification. Listeners are invited to follow a systematic survey that measures dozens of specimens, revealing patterns that echo across the chipmunks’ skulls and skins.

The narrative blends rigorous fieldwork with meticulous museum research, describing how collections from Kansas, Michigan, Chicago, and beyond were measured with eyepiece micrometers and illustrated by the author's own hand. Along the way, the book highlights subtle age‑related changes, occasional oddities, and the surprising stability of these bones across individuals. It’s a concise, accessible look at how a single anatomical trait can become a powerful taxonomic tool, offering a fresh perspective on the diversity of Western North America’s chipmunks.