The striking olive dorsum of the Olive-backed Pocket Mouse is set off by a yellowish stripe on the side and a white underside. This is the only species of pocket mouse east of the Rocky Mountains whose range extends well into Canada. Learn more about the Perognathus fasciatus, more commonly known as an Olive-backed Pocket Mouse, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.