Discovering 6 Functions of Guard Hairs in Dogs
The functions of guard hairs in dogs are several and all of them are very fascinating to discover.
Dogs come in a vast array of different shapes and sizes, and one defining feature of particular interest is their coat.
With many different breeds of dogs, a dog's coat boasts a variety of characteristics which makes learning about them so fascinating.
In this article, we will be taking a closer look into a dog's guard hairs which compose the dog's top coat.
Following are several fascinating facts about guard hairs in dogs and what makes them so special.
Single and Double-Coated Dogs
Dog coats can be single or double, and whether your dog has one or the other grossly depends on important factors such as the climate in which your dog originated from.
Single-coated dogs, as the name implies, only have a single layer of hair; therefore, they lack an undercoat.
Examples of dog breeds with a single layer of hair include several breeds designed to tolerate well warm climates such as the Chihuahua (Mexico), Azawakh (Egypt), Basenji (Congo) Cirneco dell Etna (Sicily).
Just like our summer sweaters, their coats are light and not meant to provide warmth and insulation during the frigid winter weather as seen in certain places.
Double-coated coats, instead, as the name implies, are comprised by a top coat which contains coarse guard hairs, and a softer undercoat, which contains soft, downy-like hairs.
Just like our winter coats, doggy double-coats are composed by an inner layer meant to provide insulation and an outer layer that is meant to be weather-repellent.
Examples of dog breeds with a double coat include several breeds meant to tolerate well cold climates such as the Bernese Mountain dog (Switzerland), Siberian husky (Siberia), Alaskan malamute (Alaska) and Newfoundland (Canada).
In this article, we will be focusing in particular on the dog's guard hairs.
Comparison of single and double-coated dogs
What Exactly are Guard Hairs?
Guard hairs are part of a dog's top coat or outer coat. They consist of the longer and coarser hairs that grow above the undercoat, which as seen, is a shorter and denser layer of hair that grows closer to the skin.
Guard hairs are usually straight, although they can be wavy or curly in some breeds.
Let's discover several fascinating functions of those guard hairs in dogs, shall we?
1. Prevention of Superficial Injuries
We often imagine our dogs must have tough skin considering their history of living in the wild. Our dogs' ancestors after all were predators and had to be tough cookies to survive.
People, though are often surprised to learn that a dog's skin is not as thick as we may think.
Indeed, according to research (VK Affolter 1994), the thickness of a dog's skin ranges from 0.5 to 5 mm, with the thinnest skin found in the dog's inguinal and armpit areas.
When compared to humans, a dog's epidermis (the outermost layer of the skin), which is composed of keratinocytes, is only 3 to 5 cells thick.
Human epidermis is instead three times thicker, explains Karen L. Campbell in the book: "The Pet Lover's Guide to Cat & Dog Skin Diseases."
The main reason why dog skin is so thin is because it is covered by fur which adds layers of extra protection.
In particular, a dog's guard hairs being coarse can aid in the prevention of superficial injuries to the skin.
2. Meant to Repel Water
A dog's thick and long guard hairs are typically oily which helps with water proofing. These hairs basically help prevent water from getting deep down into the inner coat and onto the skin.
Like a slate roof, when it rains, water is transported away from the dog's body dropping down onto the sides of the dog.
This explains why many dog breeds with double coats have longer and thicker hair around the shoulders- these act as an umbrella, how fascinating is that?
The dog's guard hairs transport water away from the dog's inner core
3. Protection From the Sun
A dog's guard hairs help protect the dog's skin from the harmful UV rays.
Firstly, the guard hairs provide a physical barrier between the sun and the dog's skin.
Secondly, the long and coarse guard hairs help block a significant amount of the sun's rays from reaching the skin.
Additionally, some dog breeds are known for having darkly pigmented guard hairs which can further provide extra protection from the sun.
4. Trapping Warm Air
Did you know? Dogs have the ability to raise the hairs on their neck, back and tail. The term for this feature is piloerection and it works in a similar fashion as goosebumps in humans.
Each dog hair is equipped with a hair follicle which in turn is attached to special muscles that are known as "arrector pili."
When a dog is in a normal, relaxed state, his hair follicles will stay at a 30 to 60 degree angle compared to the skin.
Let the arrector pili muscles contract though and watch those hairs literally stand up, explains Karen L. Campbell, a board-certified veterinarian specializing in internal medicine and dermatology in the book "The Pet Lover's Guide to Cat and Dog Skin Diseases."
When us humans get cold, we develop goosebumps, while in dogs, if it's very, very cold, the contraction of the arrector pili muscles causes piloerection. The raised hairs in this case are meant to trap air radiated from the body so as to create a layer of insulation.
"A dog's hair will stand on end when he is very, very cold... When the hair stands up, an insulating layer of air gets trapped between hair shafts, so the cold air cannot get so close to the skin. It works like a down jacket." Dr. Nicholas Dodman
5. A Device for Communication
On top of guard hairs trapping air to keep dogs warm, a dog's guard hairs can be raised when dogs feel threatened, aroused or scared.
Once again, this occurs in a similar fashion as the phenomenon of getting goose bumps in humans. In dogs, this is known as 'raising the hackles'.
Dogs may raise their hairs on their neck, shoulders, back and base of their tail.
When dogs raise their hackles they appear larger and more intimidating, sort of like "Halloween cats."
Raised hackles are typically seen when dogs are feeling emotionally aroused such as when surprised, excited, scared, or threatened.
As with other body parts, it's important to note that raised hackles alone do not necessarily indicate aggression or danger, and it therefore remains important to consider the context in which it takes place, along with the accompanying body language.
Chesapeake bay retrievers have coats meant for camouflage
6. A Means For Camouflage
Some coat colors in dogs aren't just for beauty. In some dog breeds, the color and texture of their guard hairs are meant to help them effectively blend with their surroundings.
This allowed them to camouflage while hunting for animals or hiding from predators.
An example is the fascinating Chesapeake Bay Retriever's coat. This breed has a thick, wavy coat that comes in three standard coat colors: brown, sedge and dead grass.
Brown can range from a light cocoa color to a deep bittersweet chocolate color.
Sedge resembles wet sedge grass and ranges from a reddish yellow through red to chestnut shades.
Dead grass encompasses all shades of dead grass, ranging from a faded tan to a dull straw color. It's a duller version of the sedge coat color.
These coat colors share the fact that they are meant to allow these dogs to blend in with the background of the environment they worked in.
Such camouflaging made these dogs more efficient hunters as game birds hardly noticed them. A too dark coat like black or too light coat like white would create too much contrast.
References:
- Whitaker, D. T., & Ostrander, E. A. (2019). Hair of the Dog: Identification of a Cis-Regulatory Module Predicted to Influence Canine Coat Composition. Genes, 10(5), 323. https://doi.org/10.3390/genes10050323
- Karen L. Campbell: "The Pet Lover's Guide to Cat & Dog Skin Diseases."
Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice or behavioral advice. If your dog is acting sick or aggressive please consult with a qualified professional for proper diagnosis and treatment.
