Chihuahua or Chis or Purse Dog is the smallest breed of dog in the world. The name of the Dog (Chihuahua) is based on the largest state (Chihuahua) of Mexico by area as it is ascended from the same state. This breed of dog is also the oldest breed in the American continent. This breed of dog was brought to Europe in 16th century by Christopher Columbus.
Generally, the height varies between six and ten inches but must not weigh more than six pounds according to British and American breed standards. This very intelligent and good watch dog has lots of variation within the breed. Some of the Chihuahua have long coats while some have smooth coats. Short coated Chihuahua are smooth while long coated are slightly curly. They also have diversity in coat colors and they have two distinct head shapes (an apple-shaped head or a deer-shaped head). Rounded heads, close-set eyes, and relatively short ears and legs are characteristics of Apple heads variety of Chihuahua while flat-topped heads, more widely set eyes, larger ears, and longer slender legs describes Deer heads Chihuahua.
image credit:By Vindhyana (Own work) [CC-BY-3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
These are one-person dogs and do not accept strangers and bark a lot. In some cases they may become overprotective for the person which make them unsuitable for households with children. Chihuahua is one of the longest living dog breed which can live up to 16 years or more. Chihuahuas are prone to eye infections or eye injury due to their large eye shape. Chihuahuas love their dens. They will often burrow themselves in pillows, clothes hampers, and blankets, deep in the dark and safety of their den. They also enjoy time in sunlight. The Chihuahua is harder to train than most other dog breeds but Chihuahuas are low-maintenance dogs when it comes to grooming. He learns new commands more slowly than the majority of other breeds. You will need to be extra patient when Training them.
Apple-headed chihuahuas are the only breed of dog to be born with an incomplete skull. They can have moleras, or a soft spot in their skulls. Signs of hypoglycemia (Low blood sugar), which include lethargy, sleepiness, uncoordinated walking, unfocused eyes and spasms of the neck muscles or head pulling back or to the side, fainting and seizures are found in Chihuahua puppies. Overfeeding a Chihuahua can be a great danger to the dog's health, shortening its life and leading to diabetes. Chihuahuas are prone to eye infections or eye injury as in other breeds with large protruding eyes. Expert veterinary attention in areas such as birthing and dental care are required by this breed.
Chihuahua was recognized by AKC (American Kennel Club) in 1904.