The smallest breed of dog in the world, the Chihuahua has a debated history. It was long thought to be a true native of Mexico. Experts claim however, that the Aztecs crossed the Chinese crested dog and the Techichi, a small, hairless, non-barking Asian dog brought to Mexico, to create the Chihuahua. The saucy Chihuahua has earned its place as a favored toy dog. Easily carried in one hand, the Chihuahua is a popular companion dog.