The Thai Ridgeback is an ancient breed of dog formerly unknown outside of Thailand. They are also known as a Mah Thai Lang Ahn. The Thai Ridgeback is one of only three breeds that has a ridge of hair that runs along its back in the opposite direction to the rest of the coat. Eight distinctive ridge patterns have been identified. The Ridgeback is a muscular, medium-sized pariah-type dog with a wedge-shaped head, triangular-shaped prick ears, and a very short, smooth coat.