chipmunk (n.)

"small striped squirrel of eastern North America, 1829 (also chitmunk, 1832), from Algonquian, probably Ojibwa ajidamoo (in the Ottawa dialect ajidamoonh) "red squirrel," literally "head first," or "one who descends trees headlong" (containing ajid- "upside down"), probably influenced by English chip and mink. Other early names for it included ground squirrel and striped squirrel.