Whiskers over a dog's eyes, may appear to be in a peculiar place for hair to grow, but Mother Nature had a strategic design in mind and those hairs on a dog's face weren't just scattered around in a meaningless fashion. In a previous article, we found some interesting findings on why dogs have whiskers under the chin, but this time around instead, we'll be looking at those whiskers over the eyes.
Not What They Seem
Some people may assume that those hairs above the dog's eyes are the equivalent of human eyebrows. Eyebrows in humans are there for a specific purpose, preventing salty sweat from falling down from our foreheads all the way down into the eye socket. The eyebrow's arched shape, with a slant to the side, allow sweat or rain to flow sideways towards the nose or sides of the face away from the eyes.
The eyebrows also trap debris like dandruff preventing it from falling into the eyes, not to mention their role in communication. Dogs do not have eyebrows because they don't sweat as we humans do, explains Stanley Coren, a psychology professor and neuropsychological researcher in the book "How to Speak Dog."
A Lesson in Anatomy
When we think of dog whiskers, our first thought goes to the long, horizontal ones located on the dog's muzzle, right on the upper lip. Those are called mystacial whiskers, as they resemble a mustache. Other than those though, dogs have several other groups of whiskers on their faces and these sets of whiskers have different names related to their location.
The ones by the back of the dog's cheek are known as genal whiskers, the ones sprouting from a mole-like spot under the chin are known as interramal tufts, and finally, the ones above the eyes are known as supraorbital whiskers.
A Warning Device
Whiskers, also known as vibrissae, are quite different from other hairs found on dogs. First off, they are stiffer and thicker, and they tend to grow in groups. Whiskers also sprout from a well-innervated hair follicle that's meant to provide dogs with sensory information pertaining their spatial location. The term vibrissae, which comes from the Latin word "vibrio," meaning to vibrate, is used to depict these hairs for a good reason.
When something in the dog's environment rubs against the whiskers they "vibrate" and work sort of like antennas relaying important information to the brain pertaining the dog's surroundings.
For instance, those whiskers can help an animal determine if he can squeeze through tight spaces without getting stuck, explains science writer Kathleen M. Wong.
A Protective Role
Those whiskers above the dog's eyes are particularly important as they play a protective role. Dog eyes are quite vulnerable to being poked and injured by objects in the dog's environment. The supraorbital whiskers sort of act like extensions of the dog's eyelashes, protecting the eyes and triggering a reflexive blinking reaction so the eyes close before something ends up potentially injuring them.
The supraorbital whiskers therefore help protect a dog's eyes. You may notice this when you pet your dog's head and inadvertently tap into those hairs which cause the eye on the same side of the face to blink.
Did you know? While people with 20/20 vision have excellent visual acuity, a typical dog has a visual acuity of 20/75 . Dogs therefore don't have very good visual acuity, which means that they don't see clearly and crisply tiny details as we humans do, explains American professor of animal science at Colorado State University, Temple Grandin in the book "Animals in Translation."