Why Do Dogs Have Whiskers?

By Leslie Gillette, DVM on Dec. 14, 2021

Ever wonder why dogs have whiskers? Each whisker plays a vital role in a dog’s sensory perception, and dogs can also communicate their emotions through their whiskers.

Here’s a closer look at what dog whiskers are, what they do, whether they grow back when they fall out, and whether you should ever cut your dog’s whiskers.

What Are Dog Whiskers?

Dog whiskers, or vibrissae, are specialized hairs that grow above a dog’s eyes and on their cheeks, muzzle, and chin. Whiskers and dog hair are both made of keratin, but whiskers have a tapered tip and are much thicker and more flexible than regular dog hair.

Whiskers that grow above a dog’s eyes are called supraciliary or supraorbital. Whiskers on a dog’s cheeks are called genal. Muzzle whiskers, which are typically the most abundant, are called mystacial (derived from the Greek root word for mustache). Dogs may also have a cluster of whiskers called an interramal tuft that grow from a mole under their chin.

The length of facial whiskers generally correlates to the size of the dog, and particularly to head width. Muzzle whiskers tend to be shorter toward the nostrils and longer toward the cheek. Whisker color is usually influenced by coat color(s), although this may change with age or secondary to skin infections, trauma to the skin and follicles, or chemotherapy drugs.

Do All Dogs Have Whiskers?

Yes, all dogs have whiskers, including traditionally hairless breeds, although the length and number may vary by breed. Curly coated breeds can have whiskers that grow curled rather than straight, but these whiskers serve the same vital role in sensory perception.

Why Dogs Have Whiskers

Dog whiskers have two major functions: helping dogs understand and sense their environment and conveying emotions.

Sensing the Environment

Dog whiskers are present at birth and are some of the first hairs to develop on newborn puppies. This early development is thought to play a vital role in helping newborn pups find their mother’s nipples and nurse before their eyes are fully open (usually around 10-14 days).

Dog whisker follicles contain clusters of tactile receptor cells (Merkel cells) that are essential for sending signals to the brain. If a whisker is touched by another object, or air currents move a whisker, that vibration transmits nerve impulses from a dog’s whisker follicles to their brain. Whiskers can detect the size, shape, and speed of nearby objects based on the movement of air currents.

Whiskers in different areas give a dog specific information about their environment:

Muzzle Whiskers: Mystacial whiskers along the muzzle extend toward an approaching object to help determine the shape, proximity, and texture of nearby surfaces as a dog moves their head back and forth. These whiskers help dogs detect food and water and measure distances.
Eye Whiskers: Superciliary/supraorbital whiskers detect potential threats to the eyes by responding to tactile stimuli or air currents. When the whiskers are moved, they send signals to a dog’s brain that trigger the blink reflex to close their eyelids.
Cheek Whiskers: Genal whiskers help with peripheral perception of the environment, such as navigating through tight spaces and keeping a dog’s head upright while swimming.
Chin Whiskers: Interramal whiskers grow from a mole under a dog’s chin. These moles contain clusters of cells that provide sensory and tactile information to the brain. They are incredibly useful in detecting food, water, and other objects that are out of the normal field of vision.

Conveying Emotions

Dog whiskers can also communicate emotions, such as happiness or anxiety when a dog is in a stressful situation.

Dogs who are relaxed often have their whiskers resting flat against their face. Happy dogs will often elevate their supraorbital/superciliary whiskers.

Dogs who are scared or perceive an immediate threat in their environment will often flare or twitch the muzzle whiskers out and downward, toward the threat. Muzzle whiskers also disperse pheromones as a means of communication.

Dog Whiskers vs Cat Whiskers

Cat whiskers play the same role as dog whiskers. Cat whiskers will typically grow to be as long as cats are wide to aid with balance and jumping ability, detection of food/prey, and the ability to navigate in the poor light settings.

Longer whiskers are typical in larger, longer-haired cats versus hairless cats or those with curly coats, where whiskers may be present in sparse numbers, or curled rather than straight. Cats also have whiskers clustered on the back of each foreleg, whereas dogs do not.

Should You Trim Dog Whiskers?

No, you should not trim your dog’s whiskers. They are vital for normal sensory perception and balance, so shortening their whiskers or cutting them off may throw off your dog’s balance, movement, and ability to sense environmental cues.

Removing whiskers by any means may cause significant stress to a dog. It affects their sensory function and can cause disorientation and a temporary disruption in normal activities like hunting, swimming, and play. In some dogs, trimming whiskers may cause aggression as a stress response.

Your dog’s sensory ability may be absent or diminished until their whiskers are able to grow back, and it can take several weeks for them to grow back to their mature length.

From an animal welfare perspective, trimming or plucking whiskers is considered an amputation of a functional sensory organ rather than a cosmetic improvement, and it has been banned in several European countries. plucking whiskers can be extremely painful and may cause bleeding.

If you cut your dog’s whiskers accidentally, it won’t hurt, and they will grow back. Be very cautious when trimming your dog’s fur anywhere near their whiskers.

Do Dog Whiskers Fall Out?

Yes, whiskers are shed like other hair on a dog’s body. It can take several weeks for a new whisker to grow to its mature length. Broken, brittle whiskers can be an indicator of age, poor nutrition, or other underlying health concerns (mange, stress, hormonal imbalance, skin infections such as ringworm, etc.).

Alopecia areata is a condition that causes dogs to lose hair and whiskers from their face, head, or ears. Dogs can also lose hair on their legs and trunk in more severe, generalized cases. Alopecia areata may resolve spontaneously in mild cases or can be treated with drugs such as cyclosporine in more severe cases.

References

Coren, Stanley. September 2011. “Why do dogs have whiskers?” Psychology Today. https://www.psychologytoday.com/us/blog/canine-corner/201109/why-do-dogs-have-whiskers
Coren, Stanley. December 2019. “The Surprising Reasons Why Dogs Have Whiskers”. Psychology Today. https://www.psychologytoday.com/us/blog/canine-corner/201912/the-surprising-reasons-why-dogs-have-whiskers
Doring D., Bartels A., Erhard M. June 2020. “The importance of the tactile hairs in domestic dogs and the problem of trimming these from an animal welfare perspective”. (Abstract only) https://pubmed.ncbi.nlm.nih.gov/32557495/
Grant, Robyn A. and Goss, Victor G. A. May 2021. “What can whiskers tell us about mammalian evolution, behaviour, and ecology?”. Mammal Review. https://onlinelibrary.wiley.com/doi/full/10.1111/mam.12253
Ramirez G A., Rodriguez F, Quesada O, Herraez P, Fernandez A, Espinosa de los Monteros A. June 2016. “Anatomical Mapping and Density of Merkel Cells in Skin and Mucosae of the dog”. The Anatomical Record, Vol 299, Issue 9, pp. 1157-1164.
Scarampella F., Roccabianca P. April 2018. “Alopecia Areata in a Dog: Clinical, Dermoscopic and Histological Features”. Skin Appendage Disorders (4)2: 112-117. doi: 10.1159/000479781. Epub 2017 Sep 9.

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