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Understanding A Dog’s Double Coat

A double coat on a dog consisits of two layers of hair. On the top layer you will find the guard hairs and below that is the softer undercoat. The density of the undercoat depends on the breed.

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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 topcoat (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 that will create skin issues such as hot spots.

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 airflow through the guard hairs and reach the skin while guard hairs will keep the dog protected from the harmful rays of the sun.  (Check out our post on common grooming tools used for the Newfoundland.)

landseer newfoundland in full coat


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.

Shaving a double coat down to the skin.

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 dogs 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. 

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Tuesday 16th of April 2019

Great article thank you! I now know a lot more about double coats. Two coats doesn't seem enough for the amount of fluff there ;P


Sunday 20th of November 2016

Hi Jennifer,

This is my first visit here.

What a great article on double coats!

I have 2 German Shepherds and 1 GSD cross, who all have double coats - yes, even my limited edition Lexi inherited a double coat.

It's coat blowing season here in our house right now and we're combing twice daily. I've also found that giving my 3 baths just as the blowing season starts helps loosen their hair making it easier to remove.

A friend of mine has 2 sibes and I've not been able to convince her that shaving her dogs is a bad idea. We live in Africa, so the summer sun is harsh here. Now that you've said it too, perhaps she'll listen!


Monday 16th of May 2016

Those double coats are so thick and fluffy, but I always imagined they could be "double work" too!

Misty Shores Chesapeakes

Saturday 14th of May 2016

Nice explanation of double coated breeds.

Russell Wilkinson Rph

Thursday 12th of May 2016

We are on our fourth Newfy and have had large and giant breeds fo over forty years. Once you see what a dog drier blower will do you will be amazed. What use to be grueling work for hours is now a snap. Check out We use the K 9 III. Expensive yes but worth every cent if you own a large or giant double coat breed. In addition our LuLu (brown Newf) loves the dryer, she curls up with it on the deck and comes running when it is turned on. See erinwilkinson or her Facebook page to see photos. P.S. I am a pharmacist and have no affiliation with the company or it's sales.

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