The ear can detect a time difference as slight as 30 microseconds and smaller differences ... The measurements were made on a 5x scale model and reduced to human pinnae size (after Batteau and Plante, ...

The pinnae of mice and rats are generally large enough to punch/notch after 2 weeks of age. Figure 2: (a) Ear punching/notching is a semi-permanent to permanent rodent identification method.