The coats of domestic dogs are of two types: "double" becoming common in dogs (in addition to wolves) originating from colder climates, produced up of the coarse guard hair plus a smooth down hair, or "solitary", with the topcoat only. Breeds could have an occasional "blaze", stripe, or "star" https://donovanlesen.spintheblog.com/32149948/the-only-guide-to-dogs