Grulla is a horse coat color that can occure in any breed. The dunn delution (horses with a dorsal strip) delutes or changes a horses original coat color. The dun gene turns a bay coat color into a yellowish coat color with black mane and tail with a dorsal stripe (Classic dunn). The dun delution lightens a sorrel body coat color but does not affect the color of the mane and tail (claybank dun) The dunn delution on a true black horse will produce a grulla (mousy grey color with black mane and tail. The dunn delution is not to be confused with the creme delution which delutes sorrels to palominos and bays to buckskins.