Rather than being bred down from a larger breed, the Chihuahua is the only toy breed that is naturally small.
The Chihuahua has a well rounded, apple shaped head. The muzzle is tiny in contrast to the head, will be slightly pointed, and either have a level or scissors bite. Ears are large and erect, spaced far apart and will flair to the sides when relaxed. Their eyes are round and large (but not protruding), very expressive, and should either be dark or ruby colored .The nose is short, pointed, and black. Light-colored eyes, and pink noses are allowed in blonde-colored dogs.
The body is robust and compact, with well sprung ribs. Measurements from wither to tail should be longer than from withers to ground. Shorter bodies are preferred in males. The neck is slightly arched, sloping into lean shoulders, and continuing down into a level topline. Their front legs should be straight, short, and square-shaped, with the back legs being well-muscled and thin. The feet are small and dainty with well split toes. And finally, the long sickle-shaped tail should curl, looping over the back with the tip just barely touching the back.
The AKC recognizes two different variations of coats: the longhaired and the shorthaired. Both variations are minimum to average shedders.
A shorthaired Chihuahua's coat should be smooth and glossy, whilst being a little coarser than a longhaired Chihuahua; an undercoat is allowed. The coat should be a little longer on the body than the head and ears; the tail should be furry. A ruff around the neck is preferred.
The longhaired Chihuahua's coat should be soft, and either lay flat or slightly curly; an undercoat is also preferred. Ears, feet, front and back legs should have feathering; the tail should be plumed. It is also desirable to have a large ruff around the neck.
Though the exact nature of where or how the Chihuahua came to be, there are many speculations of possible ways they happened to come about.
The earliest specimens were found, during the time of the Aztecs, in Chihuahua, Mexico. However, its place of origin is more likely to be the whole entire country, rather than in just the one state. Archaeologists have dated their history as far back as the 5th century A.D, as well as finding evidence of the breed in central and southern Mexico, and in South America as well.
One speculation is that a breed similar to the Chihuahua was brought to America by Spanish traders from China, where it was then mixed with the Techichi. It was then thought to have been brought to Europe at the end of the 19th century. Another theory is that the Chihuahua originated in Europe, and was then brought to America by Columbus. Proof is presented in the Sistine Chapel... a painting by Sondro Botticelli done in 1482 shows a dog resembling a Chihuahua; the painting was completed before Columbus sailed to America.
Another theory, one that is most likely, is that the Techichi were mixed with the Chinese Crested, brought from Asia to Alaska via the Bering Strait, or brought later by Spanish traders sailing from China. The Techichi, (a companion dog of the Toltecs) is believed to be the ancestors to theChihuahua. They were often sacrificed in religious Toltec rituals. Believed to guide the soul to the underworld, the sins of the human were supposed to be transferred to the Techichi because it appeased to the gods. It's apparent that they were well for cared for during life, until they were sacrificed and buried with the deceased. Both the Aztecs and the Toltecs often used the little dogs for food. While the wealthy Aztecs regarded them as being sacred, it was the commoners that saw no use for them and ate them.
Materials have been found in the Pyramids of Cholula predating 1530, in the ruins of Chichen Itza on the Yucatan Peninsula, the Monastery of Huejotzingo (built with material taken from the Pyramids of Cholula), and on the Highway from Mexico City to Puebla. All of the pictures depicter a little dog with a large round head looking very much like the Chihuahua of today.
After the Spaniards finished destroying the Aztecs, the little dogs were abandoned and left to fend for themselves. In 1850, in the ruins believed to be of Emperor Montezuma I palace, these tiny dogs were once again found. Some were brought to the United States where they were first referred to as "Texas or Arizona Dogs" because of the Texas-Arizona-Mexican borders from whence they came.
First exhibited in the United States in 1890, they were not registered by the AKC until 1904. In 1923 the Chihuahua Club of America was organized and were responsible for writing the standard, which has not been extensively changed since. It wasn't until 1952 that the Club decided to split them into two varieties depending on the coat.
The Chihuahua is a lively, charming, and intelligent breed. They are very devoted to their owners, though usually only choose one or two "favorites". Not only do they give affection, they in turn demand it. Their creative and curious nature drives them to create various ways to gain your attention. Owners of more independent breeds may find the Chihuahua too needy. Households with older children are preferred, as they can be injured easily by younger children. Valued for their loyalty and courageousness, they often become "full of themselves" and will challenge much larger dogs and strangers, and because of their size this can often result in severe injuries or possibly death. They are also very suspicious of strangers (which also makes them good watchdogs), and will not let you out of their sight. It's often said they have "terrier-like" qualities... as they are very alert, observant, bold and saucy.
They are very clannish nature, meaning that they'd choose to be with other Chihuahuas, over other dogs. Some can be quite the sun-bathers, choosing to lay in the sun for hours, thought this must be closely monitored to avoid heat strokes. Their gentleness and sweet nature makes them perfect for elderly and handicapped people. Never leaving your side, they will lay in bed with you for hours on end; preferably under the covers... of which they love.
They can sometimes be overly insecure and high-strung, which can result in separation anxiety. Chihuahus are known to bark excessively when left alone for too long. If you find yourself out of the home for long periods of time, then this is not the breed for you, as they thrive on their humans. They are also not recommended for being in a home with small children (unless raised with them) as they may resort to biting in self defense. Many tend to be fairly dog-aggressive. Their level of devotion to their humans can become a problem, as they are sometimes overly jealous of their humans relationships with one another and animals.