The hair coat, especially in animals with longer fur, naturally tends to get small tangles in it from your pet's everyday activity. The small tangles get snarled together, and dead, shedding hair and debris get caught in the snarl. As the mat gets bigger, hair from farther and farther away from the original site becomes entangled and pulls on tender skin, causing the animal discomfort.
When brushing or combing is not routine, mats become bigger and the skin may be pulled almost constantly. Each time a pet gets wet, the mat tightens more and becomes even more painful for the animal. Skin can become irritated and ulcerated from the constant pulling.
In our clinic, we have seen mats so advanced that they were nearly impossible to cut out with a pair of sharp scissors because they were so close to the skin.
One of the reasons pet owners avoid grooming is to avoid dealing with mats. As a rule, mats bigger than your thumb need special care. Your pet's skin is very delicate and thinner than yours, so if your pet is severely matted, it may be wise to consult a professional groomer.
Smaller mats can be broken apart with a mat rake or matbreaker. Larger, more involved mats must be cut out with scissors. Be careful. It is easy to cut your pet.
To groom a pet with mats:
First, note where mats are on your pet and brush around them, getting loose and dead hair out of the hair coat.
Using a mat rake or matbreaker, slowly saw through each mat starting at the end of it, slowly working your way deeper into the mat.
Be patient and attentive to your pet's comfort. Do not attempt to pull the mat out by hand.
Some mats look worse than they are, since they may not involve the undercoat. These are easy to fix. Break up the top layer with a matbreaker and comb out the undercoat.
Again, pets with larger mats, mats close to the skin, or mats which cause extreme discomfort should have the mats removed by a professional groomer.