Dogs have really sophisticated devices that help them feel their way through the world. They’re called vibrissae or “whiskers.” Because they are long and rather stiff, they act as a lever, amplifying small, light touches. All carnivores have them.
Neuropsychology tells us that the amount of the sensory cortex of the brain that is devoted to processing information from a particular body area is a good indication of how important that area to an animal’s world of perception. Of the areas of the brain that register touch information in a dog, nearly 40 percent of them are dedicated to the face. And a disproportionately large amount of that 40% of the brain is dedicated to the areas of the upper jaw that include the vibrissae. You can actually map each individual vibrissa to a specific location in the dog’s brain.
Some dog groomers are unaware of the importance of the vibrissae, viewing them as they would human facial hair – a purely cosmetic feature. So your dog groomer may cut them off to give your dog’s head a “cleaner” look. This is even more common if they know you enter your dog in conformation or other shows. Amputating the vibrissae is stressful and uncomfortable for dogs.
So why are the vibrissae so important? They have three functions:
1) they serve as an early warning device that something is near the face
2) they protect your dog from colliding with walls and objects
3) they keep approaching objects from damaging the dog’s face and eyes.
Most animals use vibrissae similarly to how a blind person uses a cane. When a dog approaches an object, the muscles that control the vibrissae move them forward. And when the dog moves his head, they “whisk” across the surface of the object. This gives the dog information about the shape and roughness of the object. This is really important because a dog’s eyes can’t focus very well on close objects. The vibrissae come to the rescue, helping him locate, identify, and pick up small objects with his mouth.
When you cut off the dog’s vibrissae, it’s also likely the dog will move more uncertainly in dim light. This is because the vibrissae don’t actually have to touch an object to let him know it’s there. These hairs are so sensitive that they also detect very small changes in air currents. As the dog approaches, for example, a couch, some of the air that he stirs up by his movement will bounce back, bending the whiskers ever so slightly, which is enough to let him know the couch is near, well before he touches it. Bats use sonar; dogs use whiskers.