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
Northern breed group Northern breed group Northern Breed Group is the name of a breed group of dogs, used by kennel clubs to classify a defined collection of dog breeds. Dogs listed in the "Northern Breed Group" may not all be of the same type of dog. Spitz-type dogs are the primary dog type of the Arctic and northern parts of the world, and the Shiba Inu, Chow Chow, Alaskan Malamute, Siberian Husky and Samoyed are being shown by genetic research to be descendents of the oldest dog types known. The Spitz or Northern-type dogs of today developed from antiquity along with humans,