The Chow-Chow is a sturdily built dog, square in profile, with a broad skull and small, triangular, erect ears with rounded tips. The breed is known for a very dense double coat that is either smooth or rough. :4–5 The fur is particularly thick in the neck area, giving it a distinctive ruff or mane appearance. The coat may be shaded/self-red, black, blue, cinnamon/fawn, or cream. :4–5 Not all these color varieties are recognized as valid in all countries. Individuals with patchy or multicolored coats are considered to be outside the breed standard. Chow-Chow eyes are typically deep set and almond shaped. The breed is distinguished by its unusual blue-black/purple tongue and very straight hind legs, resulting in a rather stilted gait. :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). :4–5 One other distinctive feature is the curly tail. :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. FCI countries, however, do allow a self-colored nose in the cream.