If you've ever taken Duke to the groomer, perhaps you've been asked about trimming his whiskers. A slight trim won't cause hurt him, but it can impact the way he feels his way around his environment. It's best to leave whiskers be.
Within a Whisker
Duke's whiskers aren't anything like the whiskers your grandfather might have grown. Technically called vibrissae, his whiskers are very different from the rest of the hair on his body. They're quite rigid and deeply embedded into his skin. Each vibrassa has a high concentration of touch-sensitive neurons at its base. When Duke brushes up against something with his whiskers, the whiskers themselves don't feel anything, but they send signals about what they encounter.
Feeling His Way
Though dogs don't use their whiskers to the extent cats do, they are helpful nonetheless. Dogs rely more on their sense of sight and smell to explore. Still, when they get up close to an interesting object, their whiskers increase their sensitivity to whatever they're exploring. The primary role of Duke's whiskers is to assist his vision and help navigation in the dark. For example, in a darkened room, Duke's whiskers can pick up a change in air currents that alerts him to a nearby wall.
Duke won't feel any physical pain if a groomer cuts his whiskers nor will it cause any medical problems. Still, this makes him uncomfortable because a significant sensory tool is no longer functioning at full range. This can be particularly problematic for older dogs with failing eyesight who rely more on the information their whiskers provide.
Just a Little Trim
Certain groomers cut a dog's whiskers because they consider this part of a good-looking dog. Others trim whiskers of dogs destined to compete in dog shows. If a groomer trims Duke's whiskers, this affects one of his sensory tools. Before you decide to allow that step, consider why you're doing it and how it will impact him. If you decide your groomer must clean him up a bit, don't allow her to pluck out his whiskers, as this can cause bleeding.