Chihuahua is a small breed of dog and is named after the Mexican state, Chihuahua. They are often devoted to a particular person in the family and they will make every effort to protect this person even if it is unnecessary. Chihuahua is known as a fearless dog, never frightened. If you see him shaking it is probably because he is cold. This dog breed has a reputation for being untrainable, which is not true, but for sure the owners need a lot of time, energy and effort to train them. They are highly intelligent, and regular and consistent training will lead them to be well-behaved dogs.