It is natural for dogs to like to scratch the mat. They may want to make it more comfortable to lie down on the mat or they want to defecate. Generally, dogs will scratch the mat before lying down to sleep, so that the dog will feel that the mat is more comfortable. Cleaning is more comfortable, and lying down will be more comfortable; another possibility is that the dog wants to defecate, but a normal dog will not defecate on the mat where it sleeps, unless it does not like the mat or the mat smells like other dogs .