Squirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots (including woodchucks), flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia. Squirrels are first attested in the Eocene, about forty million years ago, and are most closely related to the mountain beaver and to the dormice among living species. SOME say the world will end in fire. Some say ice. Some say coordinated kamikaze attacks on the power grid by squirrels.
Common squirrels are very busy.