No one knows exactly when the first TRD appeared, and different theories about the origin have been suggested... Because of the unique ridge characteristic, which is only shared by two recognized dog breeds; the TRD and the Rhodesian ridgeback, it is very tempted to believe that there is some connection between the breeds. The question is only how? The Rhodesian ridgeback is an African dog breed and the TRD�s origin is in Asia. Some people think that the TRD is an ancestor of the Rhodesian ridgeback. The reason for this is the fact that dogs from Asian are supposed to be ancestors to all the domestic dogs in Africa. If this is correct the origin of the ridge should be Asia.
Other people instead believe that the ridge first appeared in Africa and dogs with this characteristic coat returned to Asia together with traders. If this theory is correct, the joint ancestor of both of these two breeds with the ridge should be the extinct African Hottentott Hunting dog (the distinct characteristic of this dog was a ridge at the back).
Another theory is the one which believes that the TRD is a pure, but domestic dingo. You can probably exclude this idea. For example, studies on the inheritance of coat colours in canids indicates that the colour "diluted black" (blue) comes from domestic dogs, because the colour does not occur among the dingoes. The fact that TRDs do have this coat colour indicates that there have been some crossbreeding with domestic dogs. How, if and which kind of dog this could be, is still a well kept secret.
Thai Dingo?