Theodore Seville is the chipmunk in green clothing and the youngest of the Chipmunks.
Theodore is the child of innocence. He is shy, loving, sensitive, gullible, trusting and naive. In short, he is an easy target for Alvin's manipulations. In fact, Theodore often holds the swing vote between his big brothers' choices of action. Simon appeals to Theodore's better nature while Alvin goes straight to bribery.