As it is well known, the human being is a social animal, which means he constantly feels the need to feel accompanied, either by humans or other species, so it sometimes is replaced by the animal human company, adopting this way animals in pets known: among the animals most recognized for company do to human beings find cats, hamsters, reptiles like iguanas, birds as Canaries or parrots, fish both saltwater and freshwater among many others, but undoubtedly the most sought after and recognized for excellence are the dogs, because they are pets that more than any other animal adapt to the way of life of human beings either in the field or in the city. The dogs come from a species of the Wolf: the difference is that the dog ceased to be wild to become pet: coming from a family of carnivores, the power of these becomes similar to that of humans, becoming in an omnivorous animal like humans, which means that they not only eat meat but they adapt to the habits of their owners. As he has been said, these animals are a species of wolves, although with the passage of time they have had crosses important to modify the size, structure and fur coming to settle in this way different breeds of dogs: what does not change is the average life span ranging in 15 years, but it has come to ensure that breeds more small with special care may arrive at the astonishing age of 20 years. While there is no absolute certainty of how this species came to adapt in such an impressive way to humans, many scientists assert that it was more for a rapprochement of the canine that domestication forced by humans. While today dogs are used for various things such as training, the company has become one of its main roles. This has not always been so since it was previously used for the defense of hunting and the Purple, but with the creation of various races, roles have also had changes and adaptations..