While there is no solid explanation for dogs’ head-tilting behavior, behaviorists have suggested several possible reasons.
One reason why dogs may exhibit this behavior is because of how they hear. Tipping their head could help them understand sounds better. If the noise is new to the dog, they might also show curiosity by wrinkling their forehead.
Studies suggest that dogs turn their heads, not just dip them to the side, to listen better. They might turn left or right depending on which side of their brain is processing the sound.
Another reason that might explain the behavior has to do with their vision. Depending on the shape of their snout, tilting their heads could help a dog see things better. But there’s not much research to prove or disprove this theory.
Moreover, researchers found that smart dogs tilt their heads when they hear a person say the name of a toy they know. They also do the same thing when given commands they’re familiar with. This has made the researchers think that when a dog bends their head to the side, they are paying extra attention.
A whistle is not a common sound for dogs.
Some dogs have floppy ears that partly or fully cover their ear openings, which can make it harder for them to hear. So, they move their heads and perk up their ears to help catch sounds better.
Therefore, when we whistle with our dogs present, they will sometimes tilt their heads to minimize the obstruction in their hearing and listen to the interesting sound as much as possible.