The Chihuahua is the oldest breed on the American continent and the smallest breed in the world.

The Shorthaired Chihuahua is graceful, quick, and cocksure. They are very adaptable and quite sturdy for a toy breed, and they can adjust to a variety of living quarters, though they should not be kept outside. They are also good traveling dogs, compact and agreeable. Some Chihuahuas are clannish, recognizing and preferring their own kind. They may also be unsuitable for small children who may not treat them with respect or be too rough with them. On the whole, they are very fun-loving and entertaining (though hyperactive) dogs.

Mature Shorthaired Chihuahuas grow to a height of six to nine inches and will weigh in between two and six pounds. The Shorthaired Chihuahua's coat should be soft, lying close to the body, and very shiny. It should be brushed occasionally or wiped over with a damp cloth. They should also have a ruff on the neck with less hair on the head and ears. The hair on tail should be furry. Check their ears for dirt and buildup and trim their nails regularly.

Chihuahuas are natives of Mexico which may have been brought to the New World by the Chinese. They are named after the Mexican state of Chihuahua where they were first introduced to the Western Hemisphere.

The Shorthaired Chihuahua may be prone to a myriad of health concerns, including susceptibility to corneal dryness and secondary glaucoma, sensitivity to cold, susceptibility to fractures, jawbone disorders, eye problems, patellar luxation, slipped stifles, heart disease, and tooth and gum complaints. Chihuahuas should not be allowed to jump from high places because they may break their brittle bones.

Some Shorthaired Chihuahuas are born with soft spots on their heads, which, in some cases, does not close fully. A dog with this condition is subject to serious injury if it received any trauma to its head.

For exercise, Chihuahuas will require an occasional walk.

Some female Chihuahuas produce milk (colostrum), which is so acidic that it can be harmful to her puppies. Symptoms observable in the puppies are whining, and refusal to nurse. In this case puppies will need to be provided a replacement milk.