According to Wikipedia, "The Chipettes are a fictional group of anthropomorphic chipmunk singers first appearing on the cartoon series Alvin and the Chipmunks in 1983. In this cartoon and related materials, the Chipettes served as female counterparts to the title characters around which the series was based. As the series progressed, the Chipettes became featured characters in their own right, starring in several episodes in which their male counterparts did not appear."