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. The earliest known squirrels date from the Eocene and are most closely related to the mountain beaver and to the dormouse among living species. The word 'squirrel', first specified in 1327, comes from Anglo-Norman esquirel from the Old French escurel, the reflex of a Latin word sciurus. This Latin word was borrowed from the Ancient Greek word , skiouros, which means shadow-tailed, referring to the bushy appendage possessed by many of its members. The native Old English word, cweorna, survived only into Middle English (as aquerne) before being replaced.
Contributions by Aranae, Seglea, and 18.104.22.168.