Chihuahua

The Chihuahua’s history is puzzling and there are many theories surrounding the origin of the breed. Both folklore and archeological finds show that the breed originated in Mexico. The most common theory and most likely is that Chihuahuas are descended from the Techichi, a companion dog favored by the Toltec civilization in Mexico;[1] however, no records of the Techichi are available prior to the 9th century. It is probable that earlier ancestors were present prior to the Mayans as dogs approximating the Chihuahua are found in materials from the Pyramids of Cholula, predating 1530 and in the ruins of Chichen Itza on the Yucatán Peninsula.[1]

Some historians believe that the Chihuahua came from the island of Malta in the Mediterranean.[2] More evidence for this theory lies in European paintings of small dogs that resemble the Chihuahua. One of the most famous paintings is a fresco in the Sistine Chapel by Sandro Botticelli dated 1480–1482. The fresco, depicting the Trials of Moses, shows a boy holding a tiny dog with round head, large eyes, big ears, and other characteristics similar to those of the Chihuahua.[3] The painting was finished ten years before Columbus returned from the New World. It would have been impossible for Botticelli to have seen a Mexican dog, yet he depicted an animal strikingly similar to a Chihuahua.
A progenitor of the breed was reputedly found in 1850 in old ruins near Casas Grandes in the Mexican state of Chihuahua from which the breed gets its name,[4] although most artifacts relating to its existence are found around Mexico City. The state borders Texas, Arizona and New Mexico in the United States, where Chihuahuas first rose to prominence. Since that time, the Chihuahua has remained consistently popular as a breed, particularly in America when the breed was first recognized by the American Kennel Club in 1904. In terms of size, the present day Chihuahua is much smaller than its ancestors, a change thought to be due to the introduction of miniaturized Chinese dogs, such as the Chinese crested dog, into South America by the Spanish.
Chihuahuas come in virtually any color combination, from solid to marked or splashed,[8] allowing for colors from solid black to solid white, spotted, sabled, or a variety of other colors and patterns. Colors and patterns can combine and affect each other, resulting in a very high degree of variation. Common colors are fawn, red, cream, chocolate, blue, and black. No color or pattern is considered more valuable than another.

The merle coat pattern, which appears mottled, is not traditionally considered part of the breed standard. In May 2007, The Kennel Club decided not to register puppies with this coloration due to the health risks associated with the responsible gene, and in December of that year formally amended the Breed Standard to disqualify merle dogs.[9] The Fédération Cynologique Internationale, which represents the major kennel club of 84 countries, also disqualified merle.[10] Other countries' kennel clubs, including Canada, Australia, New Zealand, and Germany, have also disqualified merle. However, in May 2008, the Chihuahua Club of America voted that merles would not be disqualified in the United States, and would be fully registrable and able to compete in American Kennel Club (AKC) events. Opponents of merle recognition suspect the coloration came about by modern cross-breeding with other dogs, and not via natural genetic drift