Many people would love to have the ability to shut out noise while sleeping, in the same way that we have eyelids to shut out light. If this capability exists in nature, it could offer clues to researchers in the field of sound proofing.
Are there creatures which are capable of 'switching on or off' their hearing capabilities at will? At least partially?
I don't see why this cannot be evolutionarily possible. If perception of sound was necessary to know a predator was approaching while the creature slept, then according to evolution, creatures would not have had the ability to shut out vision either.