Appearance...

Chihuahuas are best known for their small size and large erect ears.

The AKC (American Kennel Club) recognizes two varieties of Chihuahua: the long-coat and the smooth-coat. Many smooth-coat Chihuahuas have very thin hair, but other smooth coats have a very dense, thick coat.

Height and weight

Breed standards for this dog do not generally specify a height, only a weight and a description of their overall proportions. As a result, height varies more than within many other breeds. Generally, the height ranges between six and ten inches at the withers. However, some dogs grow as tall as twelve to fifteen inches.

AKC show dogs must weigh no more than six lb (2.7 kg); the FCI standard calls for dogs ideally between 1.5 and three kg (3.3 to 6.6 lb), although smaller ones are acceptable in the show ring.

However, pet-quality Chihuahuas (that is, those bred or purchased as companions rather than show dogs) can, and do, range above these weights, to ten pounds or even more if they have large bone structures or are allowed to become overweight.

This does not mean they are not purebred Chihuahuas, it only means that they do not meet the requirements to enter a conformation show. Oversize Chihuahuas are seen in some of the best, and worst, bloodlines.

Along with "mini," "pocket" and "tiny toy", "teacup" is sometimes used to describe Chihuahuas and other dogs that are very small. These and similar terms are not officially used by any kennel club or reputable breeder, and are not breeds or specific types of Chihuahua. In particular, all Chihuahuas are toy dogs; there is no such thing as a "toy Chihuahua."

Some potential buyers seek extremely small animals; very small dogs, however, are often runts. They are often unhealthy, or undernourished, or, if otherwise healthy, may suffer shortened life spans and health problems later in life due to extreme dwarfing. They are not normally suitable for breeding, and require special care.

Some breeders of Chihuahuas purposely attempt to breed very small animals, and increase the prices of the smallest dogs, or specifically advertise tiny animals. Reputable breeders disapprove of such practices, pointing out that it is difficult to predict the adult size of a given puppy, and citing the other issues discussed above.

"Deer" or "deer-faced" are terms that are sometimes used to describe Chihuahuas that do not have the breed-standard apple-domed appearance. These terms are also unofficial.

Coloring

Chihuahuas come in many colors, from solid blacks to solid whites, spotted, or a variety of other colors like fawn (tan), chocolate, blue (gray), silver, tricolored (chocolate, blue, or black with tan and white markings), brindle, and merle; and, each of these colors varies in shades and tones, as fawn can be a term to describe a tan dog from a very pale cream to a deep (almost red) tan, or any shade in between, and the chocolate coloration can range from a milky light shade of brown, to a deep mahogony brown, to a dark brown that is almost black.