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, ...

Unlike mammals, birds do not have external ear flaps (pinnae). Instead, they have ear openings hidden beneath feathers, ...

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.