BORDER COLLIE APPEARANCE:
Border Collies are balanced, medium-sized dogs with alert, keen expressions. Their double coats come in all colors, most commonly black and white, with other common colors being red and white, red merle, blue merle, and tricolor (black/tan/white). Eye color varies from deep brown to amber or blue with occasionally one eye of each color; kennel clubs differ on acceptable eye colors for show dogs. There are smooth-coated, short-haired, and rough-coated varieties. To be a good show dog, the dog's nose has to be the colour of the leading body colour; that is, if the dog is mostly black, the nose would have to be all black.
As is the case with many breeds of dogs that are still used for their original purposes, breed standards vary depending on whether the registry is more interested in a dog who performs its job superbly or a dog whose appearance meets an ideal standard. It is possible (although unlikely) for a dog to do both, but its options for competition in dog shows might be limited depending on its ancestry and on the opinions of the various kennel clubs or breed clubs involved.
For example, in the UK, there are two separate registries for Border Collies. International Sheep Dog Society and other similar organizations encourage breeding for herding ability, whereas the Kennel Club (UK) encourages breeding for a specific appearance.
Hip dysplasia is widespread among purebred Border Collies. Some Border Collie breed clubs are active in promoting research into hereditary diseases of this breed.
Border Collies are extremely energetic and require a lot of attention. They are better off in a household that can provide them with plenty of exercise and a job to do. Like most herding breeds, they will attempt to herd family members, cats, squirrels, bicycles, cars, or anything else that moves in the absence of other charges. Border Collies make bad pets for people who cannot provide a considerable amount of daily exercise, both physical and mental. Many Border Collies end up in shelters or rescue groups because families, attracted by their appearance, discover that they cannot provide the attention and effort required for this driven, active, easily bored breed - though this problem can be alleviated by having more than one dog, with Border Terriers and other Collies the most ideal companions. Among some breeders of the breed in Britain, there is a common saying: "no sheep, no collie", referring to the dog's usual unsuitability to people who just want a "smart dog". Border Collies love to play and do not always know when to stop on their own; owners must ensure that they do not overexert themselves especially in hot weather, which can be dangerous.