Chihuahua (dog) The affected chihuahua will hold its leg flexed, and foot off the ground until the quadriceps muscle relaxes and lengthens, after which the animal feels no discomfort and continues with activity. Chihuahuas are also prone to some heart-related disorders, such as heart murmurs and pulmonic stenosis, a condition in which the blood outflow from the heart's right ventricle is obstructed at the pulmonic valve. Chihuahua (dog) The Chihuahua () is the smallest breed of dog and is named after the state of Chihuahua in Mexico. Chihuahuas come in a wide variety of colors, and two coat lengths. The Chihuahua's history
Rare breed (dog) found in the American Hairless Terrier which sought to exploit a mutation. Modern dog breeds have documented descent from known foundation stock, and new breeds are often derived from older, established modern breeds. New documentation of a long established dog type, sometimes with a variation on an older name, also creates a new modern breed. The newly documented breed is then referred to as a "rare breed" as long as the number of dogs of the breed remain small. Breeds go through a recognition process by breed clubs, kennel clubs and other agencies, so that dogs can be guaranteed through