A mat refers to densely tangled clumps of fur in a pet’s coat. Loose and live hair become embedded in large masses. If your dog scratches or bites the skin or hair it becomes wet and tangled. Sometimes mats can be combed out, but once matted down to the skin, it is impossible without seriously harming the animal.
Mats can form in both the outer coat as well as the deeper undercoat. Sometime severe mats form in the undercoat and are unnoticeable because of a heavy outer coat.
Even organic matter, like weeds and stickers, can become embedded in the skin. Mats have been known to contain stool of the pet and even fly larvae that further irritate the skin. Remember, sometimes these mats and their consequences can be completely hidden from view.