The ears of real mice do not turn like Mickey Mouse's. He and Minnie are purposefully animated so that the ears look like two distinct perfect circles whichever way their heads are turned, something that has been true since the original animations in the 1920's.
Why Mickey Mouse has round ears?
Ub Iwerks designed Mickey's body out of circles in order to make the character simple to animate. Disney employees John Hench and Marc Davis believed that this design was part of Mickey's success as it made him more dynamic and appealing to audiences.Ub Iwerks designed Mickey's body out of circles in order to make the character simple to animate. Disney employees John Hench and Marc Davis believed that this design was part of Mickey's success as it made him more dynamic and appealing to audiences.