Peeking is one of my little guys favorite things to do to. He usually goes into the hide head first and than once his whole body is in curls is head around front and rests it right at the entrance.
And from what I have read lps2 is correct, but, snakes do have an inner ear and the best way I've heard snake hearing described is: Although snakes are not equipped with outer ears like people, sound waves from the air hit their skin and are transferred from muscle to bone. When the sound reaches the ear bone beneath the skull (at the jaw), it sends vibrations to the inner ear, and the sound is processed by the brain.