Understanding a Dog's Double Coat

Posted by My Brown Newfies on Apr 16th 2019

Understanding a Dog's Double Coat

Understanding a Dog's Double Coat

A dog’s hair can come in different varieties but for the most part, they can be broken down into two categories, single coat or double coat.

A dog that has a single coat has one layer of hair. A dog that has a double coat has 2 layers.

Newfoundlands, Golden Retrievers, Great Pyrenees, Labrador Retrievers, Pomeranians, Siberian Huskies, Collies, German Shepherds, Samoyeds, and Corgis are just a few of the breeds that have double coats.

So What Exactly Is A Double Coat?

A double coat is 2 layers of hair. On the top, you will find the guard hairs and below that, you will see a soft undercoat.

Guard hairs:

The top layer consists of the guard hairs. The guard hairs are the pretty hairs that you see. They act as a barrier to repel water and catch dirt and debris.

Depending on the breed the guard hairs can be long, short, curly, coarse, corded, smooth or wire. Guard hairs are the stronger part of the hair and are meant to be permanent. They are normally not lost during shedding season.


The layer underneath the guard hairs is the undercoat. It’s softer, lighter in color, shorter and thicker than the guard hairs.

The density of the undercoat depends on the breed. Newfoundlands have a thick dense undercoat. Usually, the fluffier the dog the denser the undercoat is.

The undercoat has a purpose. It acts as an insulator for the dog. It keeps the dog warm in cold, wet weather and cool in warm, humid weather.

Newfoundland dogs have a waterproof coat. When a Newfie is laying outside for hours when it’s snowing, the top coat (guard hairs) will get wet but if you part the hair and look at the undercoat, it’s usually dry as a bone. That’s the undercoat doing it’s job.

A dog will usually blow coat 2-3 times a year, depending on the breed and its environment. 

Maintenance Of A Double Coat

The thicker the undercoat the more maintenance it will need but most double coated breeds need to be brushed weekly, some daily, and more often when they are blowing their coat.

If they aren’t brushed regularly with a good dog brush or rake, mats will form and the dog’s skin will not be able to breathe creating moisture which will create skin issues such as hot spots.

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Mats can also be very painful to the dog because they pull on the skin.

In the summer months, some owners will line comb or line brush a dog that has a very dense undercoat.

Line combing is basically where you lift up the guard hairs and comb out the loose undercoat.

It’s what I do with Sherman and Leroy. It’s as tedious as it sounds but once you get the hang of it you’ll move along pretty fast.

Line combing is how many Newfoundland owners prepare their dogs for the summer.

Removing as much of the undercoat as possible will help cool air flow through the guard hairs and reach the skin while guard hairs will keep the dog protected from the harmful rays of the sun.

See our Line Combing Tutorial here!

Shaving A Double Coat Down To The Skin.

Shaving a dog’s coat in the summer is a controversial issue.

I think in our community we have people who tend to confuse the words shave and clip. When I think of the word shave I think of bald, down to the skin. When I think of the word clip I think of clipping the coat to a different length with clippers.

Unless medically necessary it’s normally not recommended to shave a dog with a double coat down to the skin because it can expose their skin to harmful UV rays which can cause serious burns.

It can also cause a dog to overheat when they are exposed to the hot sun because instead of the guard hairs being there to deflect the sun, it gets directly absorbed into the skin.

If you sit out in the sun without any protection on your skin, you get sunburned and your body temperature rises. The same goes for dogs but they get hotter faster.

Humans and dogs each have 3 layers of skin BUT the epidermis, the outer layer of the skin, is different.

Stay with me here.

The epidermis layer of skin is divided up into layers of dead cells. These cells are what protect us.

The outermost layer of the HUMAN epidermis has more layers than the CANINE epidermis. This means that the heat will penetrate through a dog’s skin and into their bodies faster than it does on humans. This is why dogs need their coat to protect and insulate them. Not to mention that dog’s don’t sweat as humans do.

If your dog isn’t going to be laying in the direct sun, this won’t be an issue.

What Happens When A Double Coat Is Shaved Down To The Skin?

It eventually grows back but the dog’s skin will be vulnerable until it does.

The undercoat will grow back first and then the guard hairs will grow back.

So the thickest part of the hair will grow back FIRST. Guard hairs protect and are meant to be permanent and take longer to grow this is why double coated puppies look fluffier than adult double coated dogs.

A common view is to think of a dog’s coat like a house. 

The walls (guard hairs) protect the interior of the house from getting damaged. The insulation under the frame (undercoat) regulates the temperature of the interior of the house.

The insulation keeps the house warm in the winter and cool in the summer by slowing down the movement of heat. In cold weather, insulation slows down the heat from leaving the house. In hot weather, insulation slows down the outside heat from entering the house.

That is what a dog’s undercoat is intended to do.

Clipping a dog short in the warmer months is different from shaving it down to the skin.

Many dog owners will give their dog a summer cut, a short cut that still leaves the guard hairs intact and does not damage the undercoat, to keep them more comfortable but they are not shaving down to the skin.

What Type Of Dogs Should Be Clipped Short Or Shaved?

Dogs that have severe matting or skin conditions may often be shaved. This will give the dog relief from painful matting and help the skin heal faster with allergy issues.

Senior dogs that are unable to stand for long periods of time to be groomed may be clipped shorter to avoid matting.

Many owners that have dogs that don’t tolerate heat and humidity well may opt to have their dog clipped to a shorter length during the summer months to make them more comfortable.

It’s important to remember that even when a dog has their coat clipped shorter they will still need to be brushed and combed regularly. Just because a dog has less hair doesn’t mean that they need less grooming.

How Long Does It Take For A Dog To Grow It’s Coat Back When It’s Clipped?

That depends on the dog and the coat but most dogs will start to grow their coat back in a few weeks to a few months.

Leroy recently had a spot on his side shaved down to the skin for a medical procedure. This happened in December and now, at the end of February, he still has peach fuzz growing in. 

See more from My Brown Newfies here!