This topic seems to be debated heavily each year as warm weather approaches. Many people will argue that clipping or shaving off the long coat is sensible: “We don’t wear our winter coats in the hot weather do we? – so why should our dog?” Those who don’t want to clip that lovely long hair often reply that “the hair has a function and beside I like the way it looks.”

We don’t want to argue, but we thought we would research this and provide some interesting facts.

First let’s look at how hair functions, particularly the so called “double coat” often found with northern breeds or those that developed in cold climates. When you look at your dog you are generally looking at the outer layer of hair called “guard hairs”, which overlay the fur and serve to protect it. This is stiffer and often longer hair. Beneath the guard hairs is usually a layer called the “underfur” which is often seen as a wooly like (soft downy) hair when you groom out the dog.

We all generally accept that this combination of hair (called “pelage”) provides insulation from the cold in the winter. This combination is not very effective as insulation until it is fairly well developed, thus cutting it short or shaving would reduce the effectiveness as insulation. But do we accept that this also insulates against heat? Generally that is a bit more difficult to go along with.

In fact, the double coat does provide insulation in the summer. The principle of insulation is that heat flows from a warmer to cooler. This is similar to how insulation works in your home. For example insulation helps stop the heat in your home from flowing out in the winter, and also helps heat from the outside from flowing into your home in the summer by providing effective resistance to that flow. It is the same principle for the dog’s coat providing insulation to prevent heat from flowing to your dog’s skin in the summer!

Still hard to swallow this concept? To help, let’s consider the example of the home and make comparisons once more. Most would feel that eventually that heat is going to get into the home. But modern day technology has thankfully provided us with air conditioning? Guess what, dogs have a heat removal system too! Dogs don’t sweat like humans so there is no evaporation from the body skin to help cool them down. Dogs mainly cool themselves by panting and loose some heat through the dilation of the blood vessels in the skin of the face, ears and feet. Panting uses evaporation to cool as the dog breaths in through the nose and out through the mouth directing air over the mucous membranes of the tongue, throat and trachea.

The basic concept is to have insulation to reduce the amount of heat flowing in, and thus reduce the amount of heat that needs to be dissipated through panting. But there are other considerations to be concerned with. Dog hair as insulation uses the principle that air is not a good conductor of heat. Like other insulation materials called “Bulk Insulation”, dog hair needs to trap air to work. Bulk insulation traps pockets of still air within it’s structure to provide the resistance to heat flow. But also like other insulation materials – if you compress them they loose their efficiency – thus mats should be avoided by using good grooming practices.

Of course you may have other reasons to clip your dog’s hair. Maybe it is just easier to maintain or maybe you just don’t have time to remove all those mats. Maybe it just makes you feel better or you like the look. Maybe there is a skin problem. If you do clip, you can of course leave a couple inches of hair to maintain some of the insulation.

A dog’s coat also helps protect against ultraviolet light. Dogs do get sunburn, so don’t clip it too short. Generally sunburn is seen where the hair is the thinnest (bridge of nose, tips of ears, underbelly). If you clip too short you may expose the body in a similar fashion. If necessary use some sort of sun screen (but make sure it is safe for your dog! Some, like Paba have been indicated as not safe for dogs). Also remember that in climates like Arizona (and possible elsewhere) sunburn can turn into skin cancer.

Of course many people clip the hair each year. Their dogs play in the water or run though fields and pick up twigs and burs and the mats would otherwise be unmanageable (and the insulation factor lost). Just be careful to leave an inch or two of fur to provide some insulation and protection from sunburn.