1. A member of the squirrel family, having pouches in its cheeks and light and dark stripes running down its head and back. It is a small rodent which burrows in the ground and is native to western America and Asia: "When Brian was a child camping in western Canada, he tried to feed a chipmunk out of his hand and he was bitten!"
2. Etymology:  comes from chitmunk, very likely from Ojibwa origin, "squirrel".