Just like humans, dogs and cats are mammals that are covered with hair. But there are differences in the hair that covers the human body. First, most humans have more hair on their heads than their arms and legs, while cats and dogs have an even distribution of hair over most of the body. Moreover, human hair grows longer on the head than the other parts of the body while certain dog breeds have hair of consistent length all over the body. Humans may have whiskers on their faces, but they are nothing in comparison to dog whiskers.

Although cats and dogs relish cleaning morsels of food off their whiskers, the long hairs have other purposes, from sensing things close to their face to communication.
What are whiskers?
Whiskers are technically called vibrissae, they are modified, unique hairs that play an important role in sensory perception. These hairs attach to important hair follicles in the animal’s skin. These hair follicles are innervated by hundreds of sensory nerves stimulated when the whisker is bumped or moved.
Sensory organs make it possible for an organism to receive stimulation from its environment and turn those signals into a piece of valuable information. Sensory organs can provide information about pain, color, temperature, and much more. Mammals are a group of animals that are warm-blooded, produce milk through mammary glands, and contain hair. Some types of mammalian hair are modified to serve a purpose.
For instance, the specialized hair of polar bears prevents heat loss and helps incubate the animal during cold temperatures. Eyelashes are a type of specialized hair that helps to keep debris out of the eyes. Whiskers are another type of specialized hair, though their function is often unknown or overlooked. Many types of animals have whiskers. Some of the most common examples of animals with whiskers are found in houses. Cats and dogs both are popular pets with numerous, easily identifiable whiskers.
Why do cats and dogs have whiskers?
The primary function of whiskers is to aid with vision, especially in the dark, by providing additional sensory information. Although, it is often called “tactical hair”, the whisker itself cannot feel anything. Objects that brush up against a whisker cause it to vibrate, which in turn stimulates the nerves in the hair follicle.
That’s why the scientific name of whiskers is “vibrissae”, which is derived from the Latin word, vibrio, meaning “to vibrate”. Cats use their facial whiskers to estimate if they can fit into narrow spaces, while the whiskers in their legs aid them in climbing trees or sensing prey.
Whiskers serve a similar purpose in dogs. Approximately 40 percent of the canine brain can detect when something touches a dog’s face, especially those areas where the whiskers are located.
Dogs and cats can also detect something even if it doesn’t actually touch the whiskers. For instance, a pet in a dark room can pick up on the fact that there is a wall nearby because of the change in the air current.
Dogs and cats can also detect something even if it doesn’t actually touch the whiskers. For instance, a pet in a dark room can pick up on the fact that there is a wall nearby because of the change in the air current.
Whiskers are protectors
These sensitive hairs respond when touched even by the smallest particles. When a tiny speck falls on the whiskers above his eye an animal will blink or shake his head and fling it off. It protects the eye which can be injured by even a tiny dust particle. While walking outside, if the whiskers on an animal’s muzzle encounter a tall blade of grass or a thorny bush, they prompt the dog to back up to avoid being scratched or poked in the eye.
Whiskers help to prevent dogs from getting into jams. As a dog approaches a narrow spot in the fence, a small area between the living room chairs, or a slender space between rocks, whiskers help the dog determine if it can fit through the passage without getting stuck or turning over the furniture. This keeps the dog out of many troubles.
Whiskers communicate emotions
The whiskers help animals in communicating emotions. For instance, when a dog is resting, the whiskers take a break. And when a dog is active so are the whiskers. A happy or curious dog will elevate the whiskers above his eyes. But if a dog is threatened, he will flare the whiskers on his muzzle and direct them forward toward the threat.
Whiskers’ protection
The whiskers of animals need protection. A good portion of a dog’s brain is devoted to processing data from touch sensors. Almost 40% of the brain’s sensory area aligns with the parts of the body that have whiskers.
When petting your animal, touch the whiskers very gently along the grain. Don’t pluck or pull on the whiskers, because it will be painful for your pet. When grooming your pet, avoid cutting the whiskers, because it may decrease your pet’s special awareness and confuse him.