The smallest breed of dog is the Chihuahua. It is named after a region in Mexico with the same name. Chihuahuas were believed to be descendants of Techichi, a slightly larger breed that was associated with Aztec royalty. However, most people now think that Spanish merchants brought Chihuahuas to Spain through trading with China and then eventually brought them to Mexico. Chihuahuas were then brought to the United States by those who visited Mexico.

Known for their large erect ears and small size, Chihuahuas come in two varieties: smooth-coat and long-coat. Chihuahuas have a wide range of heights, but are generally 6 to 10 inches tall. Chihuahuas' weights vary as well, as some weigh only 5 pounds when others can weigh more than 10. Chihuahuas also come in many colors, from black to white to spotted to gray to tricolored.

Chihuahuas are liked for their unique personality and their devotion to their owners. They are an intelligent, alert breed who can adapt well to different places because of their small stature. Chihuahuas' average life span is about 15 years. Because of their fragility and size, it is not recommended that Chihuahuas be pets for families with small children. Chihuahuas are also known to focus on one person in a family and are not fond of human relationships that that person may have. However, this can be fixed by socializing the dog. Chihuahuas are also known to prefer being friends with other Chihuahuas rather than other dog breeds. Still, most Chihuahuas tend to not understand their small size and may confront larger animals, which could lead to them getting hurt. Due to their small size, Chihuahuas are sensitive to the cold, which is why some owners dress them in dog sweaters on cold days.

Chihuahuas need special attention in dental care and birthing. They are also prone to genetic anomalies such as seizure disorders and epilepsy. Another condition to watch out for is patella luxation, as well as hydrocephalus, which is when there is water on the brain. Sadly, some puppies have this condition and die within six months of age.

They are the only breed of dog that is born with an incomplete skull. Their moleras, a soft area on their skulls, needs to be taken great care of as the skull fully forms in the first six months. Unfortunately, due to their large, protruding eyes and their closeness to the ground, Chihuahuas are also prone to eye infections.

Chihuahuas can be picky eaters, so owners must be sure to give them proper nutrition. Also, overweight Chihuahuas can suffer from joint injuries and a shortened life span.

There are also a number of famous Chihuahuas such as Tinkerbell, Paris Hilton's pet, Gidget, the Taco Bell mascot and Ren Hoek of the animated series called Ren and Stimpy.

Some buyers wish to have very small dogs, but this is often unhealthy for Chihuahuas. They can suffer shorter life spans and many problems can come out of dwarfing. They need special care and should not be treated as toys.

Chihuahuas make great pets as long as they have a strong companion and are well taken care of.