Chattering squirrels, charming coypus, and tail-slapping beavers—along with some other rodents—have orange-brown front teeth. Researchers have published high-resolution images of rodent incisors in ACS Nano, providing an atomic-level view of the teeth's ingenious enamel and its coating. They discovered tiny pockets of iron-rich materials in the enamel that form a protective shield for the teeth but, importantly, don't contribute to the orange-brown hue—new insights that could improve human dentistry.