Chattering squirrels, charming coypus, and tail-slapping beavers — along with some other rodents — have orange-brown front teeth. Researchers have produced high-resolution images of rodent incisors, 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.