They are seen in two coat types : The smooth shorthair (which needs only a quick brushing once weekly) and the longhair (which has longer hair on the ears, chest, stomach, legs and tail that needs to be brushed and combed every other day). Shedding is moderate. Common colors include white, blonde, fawn, black, black and tan and patched, although any color is acceptable. The ears are pricked, although the tips may droop slightly. The tail is long, and the head is dome-shaped.

This breed can be traced back to the ninth century A.D. as the techichi dog of Mexico's Toltec Indians. The modern version is said to have resulted deom crossing the techichi with a small hairless dog from Asia. The earliest specimens of the modern breed were found in the state of Chihuahua in Mexico, for which they were named. The Aztecs, who conquered the Toltecs, revered these little dogs as religious symbols of good fortune.

Intelligent and alert, this dog is the ultimate companion for apartment dwellers. Exercise requirements are minimal; many don't even like outdoors. Most Chihuahuas are very playful, curious and lively. Some are bold and temperamental, while others are timid and nervous. They may snap at strangers if they feel threatened. Generally, these dogs do well with obedience training, except for the ones that get too nervous around other dogs. This breed is said to be clannish, preferring its own kind to dogs of other breeds. Housetraining can be difficult, and many owners opt to paper-train. Chihuahuas are fine dogs for novice owners, good with older people and considerate of children, especially if they grow up together.

These dogs live a long time. 15 years is not unusual. They are susceptible to dislocating kneecaps, fractures, jawbone disorders, arthritis, eye problems, heart disease, tooth and gum disease and hydrocephalus (water on the brain).