|A Thai ridgeback in red|
|A "violin" ridge|
The breed has been used for such things as hunting and as watch dogs and even as carting dogs. They are known for being capable of killing cobras. Their temperament is typical of the pariah breeds, and reminds me very much of the basenji in the descriptions of its character.
|A blue Thai|
As mentioned on Dogs 101 on Animal Planet, there are few outside of their native Thailand and, though mostly a very healthy breed, they are prone to dermoid sinus.
Main source is the Association of Thai Ridgeback Owners & Fanciers. Images are from Wikimedia Commons under creative commons incenses: one, two, three.