Today, about 1000 breeds of dogs are known, but only a quarter of them have been studied, in order to know their specific behavior and differences with other breeds. This type of study has been done following a vast set of methodologies that have allowed us to know what the various breeds are for and what differences are identified between them. In this way, it was possible to determine which breeds were the most suitable to guide the flocks, which to help blind people as guide dogs, which were brought to tow sleds or save lives. The function that each breed develops is determined by its abilities and temperament. The differences between dog breeds are therefore not determined solely by their size or physical characteristics. Studies carried out dog-only Between 1950 and 1960, two scientists, Scott and Fuller, selected five different dog breeds, which were bred under the same conditions. The dogs in question were a Basenji, a Fox Terrier, a Cocker Spaniel, a Beagle, and a Shetland Shee