The Border Collie is a breed of herding dog that originated in the border country of England and Scotland. They are widely regarded as the most intelligent dog breed. Border Collies are highly energetic. They are still frequently used on farms all over the world for assisting with the handling of livestock, and they have also become popular as pet and sport dogs. Though known to be reserved with strangers, these dogs can also be protective of a human family member and affectionate to those they know. In general, Border Collies are medium-sized dogs without extreme physical characteristics and a moderate amount of coat. Their double coats can be anywhere from slick to lush, and can come in many colors, although black and white is by far the most common. Black tricolor (black/tan/white or sable and white), red (chocolate) and white, and red tricolour (red/tan/white) also occur regularly, with other colors such as blue, lilac, red merle, blue merle, brindle and "Australian red"/gold seen less frequently. Border Collies of any color with no white markings are also seen. Eye color varies from deep brown to amber or blue with occasionally one eye of each color, usually seen with merles. The ears of the Border Collie are also highly variable — some have fully erect ears, some fully dropped ears, and others semi-erect ears (similar to that of the Rough Collie). Although working Border Collie handlers sometimes have superstitions about the appearance of their dogs (handlers avoid mostly white dogs due to the fact that sheep are also white and are less frightened, this makes the sheep less obedient to the dog.), in general a dog's appearance is considered to be irrelevant. It is considered much more useful to identify a working Border Collie by its attitude and ability than by its looks. Those dogs bred for the conformation ring are more homogeneous in appearance than working Border Collies, since to win in conformation showing they must conform closely to breed club standards that are specific on many points of the structure, coat and color. Kennel clubs specify, for example, that the Border Collie must have a "keen and intelligent" expression, and that the preferred eye color is dark brown. In deference to the dog's working origin, scars and broken teeth received in the line of duty are not to be counted against a Border Collie in the show ring. Height at withers: Males from 19" to 22" (48 cm to 56 cm), females from 18" to 21" (46 cm to 53 cm). (See various breed standards for details.) Border Collies are an intelligent, biddable breed with an instinctive desire to work closely and intensely with a human handler. They are very well behaved and can be very excitable dogs. Although the primary role of the Border Collie is that of the working stock dog, dogs of this breed are becoming increasingly popular as pets. True to their working heritage, Border Collies make very demanding, energetic pets that are better off in households that can provide them with plenty of exercise and ample play with humans or other dogs. Border Collies are now also being used in showing, especially agility, where their speed and agility comes to good use which makes dog sports popular with Border Collie owners. However, in an appropriate home, with a dedicated, active owner, a Border Collie can be an excellent companion. Though they can be a wonderful choice for some households, Border Collies are not perfect pets for all people. For example, as with many working breeds, Border Collies can be motion-sensitive and may attempt to control the movements of family members, cats, squirrels, bicycles, cars, or anything else that moves if not given enough mental and physical stimulation. These dogs are also generally not suitable for households with small children. Many Border Collies who end up in shelters or rescue groups are there because owners, who may have been attracted by their appearance and intelligence, were not prepared to meet their dog's needs.
