Whenever you hear a sound that you aren’t expecting, you have some sort of reaction. Whether physical or mental, the acknowledgement of changes in your surroundings is instinctive. The same thing goes for dogs.
And their reactions are always pretty entertaining. Some dogs bark until they’re hoarse. Others jump and spin until they’re completely worn out. This dog, however, has a more cerebral response to the strange noises around him. You can see the wheels turning in his brain as he tries to figure out what these sounds are (and why they woke him from his nap).
He reacts to this situation like a human! He’s probably a terrible guard dog, but I bet he’s an awesome friend.