By the stoneage some 14'000 years ago, man had developed close social interactions with dogs. Some of the benefits that dogs provided were recognised and exploited by those early hunter gatherers. In order to get these dogs to assist in guarding, hunting and killing prey, some form of training involving an 'agreement' or 'pact' between man and dog would have to have been made. This pact would take the form that says if you do this you will be rewarded by that. To think this is probably when positive reinforcement training first started out. Dogs as a species have been by mans side side for more than 14'000 years. It is not beyond reasoning to think that it was the dog who helped man conquer earth and make it into the world we have today. No other species has evolved quite in this way. Although the earliest archaeological records indicated the earliest remains of dogs at 14'000 years. Molecular genetical analyses has been carried out in the United States of America to suggest that the effort to domesticate dogs as a species from wolves could date back more than 100'000 years. Three wolf species have been identified as possible relatives to the domestic dog. The Indian wolf, The Chinese wolf and the Asiatic wolf.