The breed is unique by their purple/blue-black tongue which no other breed has except Shar Pei, and has very straight hind legs, resulting in a rather stilted gait.[1]: 4–5 The bluish color extends to the Chow Chow's lips; this is the only dog breed with this distinctive bluish color in its lips and oral cavity (other dogs have black or a piebald pattern skin in their mouths).[1]: 4–5 Another distinctive feature is the curly tail.[1]: 4–5 It has thick hair and lies curled on its back. The nose should be black, but blue-coated Chow Chow can have a solid blue or slate-colored nose. According to the American Kennel Club breed standards, any other tone is not acceptable for contests.[6] FCI countries, however, do allow a self-colored nose in the cream.[7]