Walnuts are a favorite food of Arizona Gray Squirrels, and when they find an abundance, the squirrels soon stain their faces, paws, and undersides a distinct brownish-orange from walnut juice. Other foods eaten may include fungi, acorns, juniper berries, pine seeds, and tree flowers and buds. Learn more about the Sciurus arizonensis, more commonly known as an Arizona Gray Squirrel, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.