Why Do Dogs Have "Whiskers"?
Want to offend your dog? Call those delicate sensory receptors on his face whiskers, when the real term is vibrissae. Want to upset him? Cut them off.
Caroline Coile |
Posted: December 30, 2014, 6 a.m. PST
A dog’s vibrissae function as sensory feelers. They’re located not just on the muzzle, but on the chin and above each eye, and are some of the first hairs to grow in puppies. Each is embedded about three times the depth of a normal hair, and has a rich nerve supply. They're similar to human eyelashes that can cause the eye to shut on reflex. Try this with your dog: Touch his vibrissae on one cheek, and watch his eye on that side blink. It’s as though he had an extra set of eyelashes to warn him something’s coming at his eye. Would you like it if somebody cut off your eyelashes?
Maps of the canine brain show that a disproportionately large area is devoted to touch sensations from the area of the vibrissae---nearly 40 percent of the areas of the brain that register tactile (touch) sensations is devoted to the brain, especially the upper jaw where the vibrissae are located. Each vibrissae can be mapped to a specific location in the dog's brain, suggesting they really do impart localized information.
In many show dogs, it’s customary to cut vibrissae off for a cleaner look; and when you take your furry-faced dog to the groomer for a shave chances are his vibrissae are getting shaved off with the rest of his facial furnishings. But is this clean-shaven look depriving these dogs of an important sense?
Anecdotal evidence with hunting dogs claims that dogs with cut vibrissae tend to come back from a day of hunting with more facial scratches in comparison with those whose vibrissae are intact. That makes sense, since they vibrissae seem to be especially important in detecting objects close the face or under the muzzle where the dog either can't focus well or has his vision blocked. When the dog encounters an object the vibrissae are directed forward by tiny muscles, and then they may vibrate slightly as they are whisked over the object. They also seem to help dogs detect objects in dim light; they are so sensitive they can detect air currents bouncing off a wall, for example. Dogs without vibrissae appear to be more hesitant in dim light compared to dogs with intact vibrissae.
Cats with cut vibrissae are less active. In rats, cutting the vibrissae interferes with their depth perception, swimming ability, equilibrium, tactile maze learning, and several other functions that depend on touch.
Dogs probably rely on their vibrissae less than do cats or rats, but they wouldn't have them if they weren't important. Tell your groomer to leave them on. And don't think you have to cut them off to win in the show ring. I've never met a judge who says they notice whether they're there or not. Some breed standards specifically prohibit cutting the vibrissae. If your dog just hangs out around the house, their absence probably won't affect him much. But if he hunts, retrieves, runs agility, competes in earthdog trials or does any activity where balance and touch are important---leave them on!
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