Wait until you hear about the Chihuahua history - truly amazing!  And do you know what's also interesting about the Chihuahua, the Chihuahua is not in the Terrier group.  The Chihuahua is actually in the AKC Toy group, with breeds like the Chinese Crested, Miniature Pinscher, and the Shih Tzu.  Learn, Don't Return has covered the Shih Tzu here, and like the Shih Tzu the Mexican Chihuahua is an ancient breed that was symbolized in ancient artwork and both were sacred deities associated with gods.  The Chihuahua was associated with the god of lightning and death.  Folks were talking about 500 BC in the Mayan civilization, when the Chihuahua was called the Techichis.  And after the Mayans, the Toltec civilization carried on the Techichis legacy which was only 300 BC.  More recently the Aztecs, which conquered the Toltecs in the 12th century, continued to worship the Chihuahua.  No wonder the little guys have a determined personality, they've been in charge of some of the greatest civilizations on earth!