The smallest dog breed in the world, the Chihuahua was discovered in Mexico in 1850, and subsequently introduced to America. The popularization of the Chihuahua as a pet was a result of media coverage given to celebrities who adopt Chihuahuas as pets such as Marilyn Monroe and Paris Hilton. There are two official Chihuahua breeds recognized by the American Kennel Club today. These are the Long-haired Chihuahua and the Short-haired Chihuahua. Unofficially, other different breeds of Chihuahuas exist. These include the Teacup Chihuahua, Mini Chihuahua and Toy Chihuahua amongst others. The origins of these unofficial names were a result of Chihuahua breeders who dub their dogs accordingly based on their full grown size.

The Long-haired Chihuahua is characterized by their smooth undercoat and long overcoat. The texture of its coat is long, thin and smooth to touch. The Long-haired Chihuahua has large eyes and erect ears, similar to that of a Pomeranian. In fact, it is not difficult for most people to mistaken a Long-haired Chihuahua for a Pomeranian given such similar characteristics. Surprisingly, this Chihuahua breed sheds little hair as compared to its Short-haired cousin. As a result, it is relatively popular with people who suffer from allergies. However, its long overcoat of hair can take a relatively long time to reach its full grown length, in most cases as long as a few years. It is important for owners of this breed of Chihuahua to frequently brush the hair of their Long-haired Chihuahua to prevent tangles that may occur to the hair of the Long-haired Chihuahua. It is also important for owners of the Long-haired Chihuahua to bath their pets on a regular monthly basis to prevent fleas and to maintain hygiene standards of their Long-haired Chihuahua.

Comparatively, the Short-haired Chihuahua as its name suggests has a shorter coat of hair as compared to its Long-haired cousin. However, it tends to shed more hair as compared to the Long-haired Chihuahua. Texture of the overcoat of this breed of Chihuahua is also different as compared to the Long-haired Chihuahua. Given its shorter coat of hair, the Short-haired Chihuahua is popular amongst people living in relatively warm countries.

Unofficial breeds of Chihuahuas such as the Teacup Chihuahua, Mini Chihuahua and Toy Chihuahua. These breeds of Chihuahuas are comparatively smaller as compared to regular Chihuahuas. Amongst these unofficial breeds, the Teacup Chihuahua is the most popular as a result of extensive media coverage of Paris Hilton's Teacup Chihuahua, Tinkerbell Hilton. Spotted everywhere with Paris Hilton, Tinkerbell's small size allows it to fit snugly into the socialite's handbag. The small sized of these dogs make them popular with apartment dwellers as they do not require big open spaces as compared to other dogs. They are also relatively easy to train, sparing the owner the need to send them to dog schools for training. However, their small size results in greater fragility. These adorable dogs are extremely prone to health problems such as dehydration and respiratory problems. Their small size also means that they are unable to provide sufficient warmth for themselves, especially in colder countries.

In any case, Chihuahuas are relatively fragile pets and special attention must be accorded to taking care of them. Chihuahua adoption is also a long-term commitment as the average lifespan of these dogs is between 11 ? 18 years. Given such, its is important for potential owners to consider carefully their ability to commit to their pets before adopting one.