The pinna reflex is present from birth until 2 to 3 weeks of age. To demonstrate this reflex, hold the puppy so that its vertebral column is parallel to the floor and dorsal relative to the rest of the puppy.
The long axis of the body is rotated 90 degrees. As soon as the tilting of the head bens, the upper pinna will rise dorsally away from the body until its external surface falls toward the top of the puppy’s head and the external auditory canal is exposed. The lower pinna will point toward the ground.