Main characters
Dave
Dave has patience and sanity tested in practically every episode, song, and film he is included. Dave is the chipmunks' songwriter and producer as he plays well in piano and guitar. He tries extremely hard to keep the group focused during performances but he always has a challenge to deal with such as getting them to practice, keeping them focused, or preventing them from goofing up the songs. Alvin, the troublemaker often irritates him, resulting in Dave's famous yell, "AAAALLLLVVVVIIIINNNN!!!!!!" to which Alvin often replies with a loud "OKAY!!". Though he is stressed out at times, Dave has always been a very loving and caring father.
Alvin
Alvin is the oldest of the chipmunks even though he is not the tallest. He is usually responsible for all of the trouble, as the term “Look before you leap” does not apply to him. He is an emotional roller coaster and leader of the group. His enthusiasm is boundless. He is somewhat greedy and selfish, but loves his brothers. He is a fearless chipmunk. He'll even stick up for his little brother Theodore. He doesn't follow anybody's rules, not even his own.
Alvin's favourite things are his harmonica and his cap, which he always wears. He doesn't like anybody touching his cap, and he has no trouble in saying so, “Don't...touch...the cap!”. His signature colour is red.
Simon
Simon is the tallest and the middle child and he is the smartest among the three chipmunks. Simon possesses a very dry sense of humor as well as a keen wit. His chess master mind allows him to anticipate what he calls Alvin's "harebrained schemes" and devise a solution that is inevitably required.
Although Simon loves Alvin, Simon secretly worries about the fact that they share the same gene pool. However, Simon will drop whatever he's doing to help his brothers whenever they need him. Simon's signature color is blue.
Theodore
Theodore is the youngest chipmunk. He is the child of innocence. He is shy, loving, gullible, sensitive, trusting and naive. He often holds the swing vote between his two brothers' choices of action. Simon appeals to Theodore's better nature, while Alvin goes straight to bribery, often with sweets or other foods, as Theodore is also known for his sizable appetite.
His sweet nature usually makes him an easy target for bullies, but then they'll have to answer to his big brothers Alvin and Simon. Little known facts are that Theodore is afraid of heights, hates roller coasters, and sometimes carries his teddy bear with him.Theodore's signature colour is green.
(reference from wikipedia)