We who have the longhaired breeds struggle with mats. It seems that one day your dog has a few knots and tangles which you religiously comb out and the next day, boom! You have mats and your dog will have to be shaved down to start anew.
Many customers ask us not to shave their dogs down to the skin. You probably chose your dog at least in part because of his or her beautiful coat and you don't want to lose it. But here's the thing with mats. Once you get them you have to shave close to the skin to be humane. Also, you wouldn't want the cost of attempting to preserve the coat as it would take many hours longer to do.
What happens is that the hair of many breeds known for mats has a rough texture on the hair shafts that tends to knot and tangle where hairs rub together. The knots and tangles twist in the friction areas, such as under the "arms" and behind the ears or wherever your dog or cat sleeps or rubs. As they twist, the knot takes up more and more of the "slack" hair, making it larger and tighter to the skin. Thus, a fully formed matt lies right up against the skin, often getting impregnated with skin and dander and making a big mushy mess.
If you're old enough to remember using a telephone with a spiral cord between the phone and the receiver, you'll remember how each time you picked up the receiver it twisted that cord and over time the receiver got so tangled and twisted that you couldn't really put it up to your ear and you had to untwist and tangle the thing.
That's how it is with mats. However, the phone doesn't have sensitive skin, and your dog does, so pulling on the mat to untangle it hurts your dog. The quickest and least painful solution is to shave under them. This removes them with no irritation to your dog and less cost to you. Sometimes if you catch them while they're still loose knots you can preserve a little bit of coat length, but if you're feeling mats, they're already close to the skin and you'll have to shave close.
The good news is that hair grows fast. If you do have to shave your dog down, his or her hair will be back in a few weeks and you can start again. If you keep your dog's coat less than 1" long and brush every day you'll never be troubled with mats. And if you mess up, as most of us do, and the mats get away from you, we can give your dog a stylish short clip and get him clean and cute again. No worries.