This is a photo I took last year in Michigan of an Eastern Chipmunk in a Rhododendron bush. They gather many seeds, nuts and fruit in preparation for their winter sleep. It is not a real hibernation though, because they wake up periodically to eat from their store of food. They do have a somewhat lower body temperature when they sleep, however. There are many different regional chipmunks in different areas across the country. It can be rather hard to tell them apart. I reviewed a guidebook last year, The Audubon Guide to Mammals, that has a section that covers different kinds of chipmunks.