The coats of domestic dogs are of two versions: "double" currently being prevalent in dogs (together with wolves) originating from colder climates, made up of a coarse guard hair along with a smooth down hair, or "solitary", with the topcoat only. Breeds could have an occasional "blaze", stripe, or "star" https://tysonwdilp.dailyhitblog.com/37242883/the-definitive-guide-to-dogs