A hungry squirrel running bravely to eat nuts fast

Fossils of the earliest known squirrel species come from Eocene strata. It was a long time between 65 million and 35 million years ago. At that time, dinosaurs had just become extinct, mammals had not yet gained control on land, the Tibetan Plateau had not yet become land, Europe and North America were still connected by land, and South America was a huge island.