On the other hand, the Chipettes may have mutated the other way like Splinter. Jeanette Miller was a human, but after being exposed to toxic waste, she was turned into a chipmunk. Why else does April O'Neil's friend in Teenage Mutant Ninja Turtles look exactly like her??
- In "May the Best Chipmunk Win", an episode from season 1, has Alvin and Brittany running for school president.
- In "Romancing Miss Stone", Alvin talked about how his ninth birthday is coming up.
- In "My Pharoah Lady", Brittany makes a bet with Prudy Snooty that if King Tut was not real by midnight, Brittany would have to resign from the Queen of the Halloween Carnival, implying the events of season 5 take place when the Chipmunks go to 4th grade.
- In "Alvin, Alvin, Alvin!", Alvin does not win Class President that year, also indicating that season 5 takes place during 4th grade, while the past four seasons were during 3rd grade.
- In "Bigger!", Dave mentions that the boys are in 4th grade when talking about signing up for a record deal. This further shows that the Murakami-Swenson-Wolf and DiC episodes (1988-1990 collectively) picked up from the last Ruby Spears season.