The Yorkshire terrier is a small dog breed of terrier type, developed in the 1800s in the historical area of Yorkshire, England. The defining features of the breed are its small size, less than 3.2kg or 7.03 pounds, and its silky blue and tan coat. The breed is nicknamed Yorkie and is placed in the Toy Terrier section of the Terrier Group by the Fédération Cynologique Internationale and in the Toy Group or Companion Group by other kennel clubs, although all agree that the breed is a terrier. A winning show dog and a popular companion dog, the Yorkshire terrier has also been part of the development of other breeds, such as the Australian Silky Terrier.
For adult Yorkshire terriers, the importance is placed on its coat colour, its quality, and its texture. The hair must be glossy, fine, straight, and silky. Traditionally the coat is grown-out long and is parted down the middle of the back, but "must never impede movement."
Yorkies have very soft coats. Yorkies have two types of coats; a silky or a soft. The silky coats are the coats of the show dogs. The soft coats are short and do not need to be brushed very often.
From the back of the neck to the base of the tail, the coat should be a dark gray to a steel-blue, and the hair on the tail should be a darker blue. On the head, high chest, and legs, the hair should be a bright, rich tan, darker at the roots than in the middle, that shades into a lighter tan at the tips. Also, in adult dogs, there should be no dark hairs intermingled with any of the tan coloured fur.
Adult Yorkshire terriers that have other coat colours than the above, or that have woolly or extra fine coats, are still considered to be Yorkshire terriers, and will be just as good of a companion as a dog with the correct coat. The only difference is that atypical Yorkshire terriers should not be bred. In addition, care may be more difficult for "woolly" or "cottony" textured coats, or coats that are overly fine. One of the reasons given for not breeding "off-coloured" Yorkies is that the colour could be linked to a genetic defect that may affect the dog's health.
A newborn Yorkie puppy is born black with tan points on the muzzle, above the eyes, around the legs and feet and toes, the inside of the ears, and the underside of the tail.. Occasionally Yorkies are born with a white "star" on the chest or on one or more toes. These markings fade with age, and are usually gone within a few months. A white "star" on the chest is generally an indication that the puppy will be a good coat grower in quantity, but not necessarily quality.
It may take up to three years or more for the coat to reach its final colour. P. H. Coombs, writing in 1891, complained about show wins awarded to puppies, when the dog's coat does not fully come in until three or four years old, "and the honour of winning such a prize (for a puppy) can therefore be of but little practical benefit to the owner" since the adult dog's colour cannot be exactly predicted.
The typical fine, straight, and silky Yorkshire terrier coat has also been listed by many popular dog information websites as being hypoallergenic. In comparison with many other breeds, Yorkies do not shed to the same degree, only losing small amounts when bathed or brushed. All dogs shed, and it is the dog's dander and saliva that trigger most allergic reactions. Allergists do recognise that at times a particular allergy patient will be able to tolerate a particular dog, but they agree that "the luck of the few with their pets cannot be stretched to fit all allergic people and entire breeds of dogs."