Collies form a distinctive type of herding dogs, including many related landraces and standardized breeds. The type originated in Scotland and Northern England. Collies are medium-sized, fairly lightly-built dogs, with pointed snouts. Many types have a distinctive white color over the shoulders. Collies are very active and agile, and most types of collies have a very strong herding instinct. Collie breeds have spread through many parts of the world (especially North America and Australia), and have diversified into many varieties, sometimes mixed with other dog types.
Some collie breeds have remained as working dogs for herding cattle, sheep, and other livestock, while others are kept as pets, show dogs or for dog sports, in which they display great agility, stamina and trainability. While the American Kennel Club has a breed they call "collie", in fact collie dogs are a distinctive type of herding dog inclusive of many related landraces and formal breeds. There are usually major distinctions between show dogs and those bred for herding trials or dog sports: The latter typically display great agility, stamina, and trainability, and most importantly intelligence.
Common use of the unmodified name "collie" in some areas is limited largely to certain breeds – the name means Rough Collie by default in parts of the United States, and Border Collie by default in many rural parts of Great Britain. Many collie dog types do not actually include "collie" in their name – for example the Welsh Sheepdog.
The exact origin of the name collie is uncertain; it may derive from the Scots word for 'coal'. Alternatively it may come from the related word coolly, referring to the black-faced mountain sheep of Scotland. The collie name usually refers to dogs of Scottish origin which have spread into many other parts of the world, often being called sheepdog or shepherd dog elsewhere.
Collies are generally medium-sized dogs of about 22 to 32 kg (48 to 70 lb) and light to medium-boned. Cattle-herding types are more stocky. The fur may be short, or long, and the tail may be smooth, feathered, or bushy. In the 1800s, the occasional naturally bob-tailed dog would occur. The tail can be carried low with an upward swirl, or may be carried higher but never over the back. Each breed can vary in coloration, with the usual base colors being black, black-and-tan, red, red-and-tan, white with a colored head with it without other body coloration of sable, black and tan, blue merle, sable merle sable. They often have white along with the main color, usually under the belly and chest, over the shoulders, and on parts of the face and legs, but sometimes leaving only the head colored – or white may be absent (unusual) or limited to the chest and toes (as in the Australian Kelpie). Merle coloration may also be present over any of the other color combinations, even in landrace types. The most widespread patterns include sable, black and white, black and tan and tricolour (black-and-tan and white).
Collies range in trainability from the "average" to very biddable. The Border Collie is also the breed most in need of a job, while other collie breeds fit well into an active family lifestyle. The breed is also known for its sensitivity and awareness of emotions in people.
A working member of a collie breed, such as the Border Collie, is an energetic and agile dog with great stamina. When in fit, working condition they are able to run all day without tiring, even over very rough or steep ground. Working collies display a keen intelligence for the job at hand and are instinctively highly motivated. They are often intensely loyal. Dogs of collie type or derivation occupy four of the first sixteen ranks in Stanley Coren's The Intelligence of Dogs, with the Border Collie being first. These characteristics generally make working strains suitable for agility; in addition to herding work they are well suited to active sports such as sheepdog trials, flyball, disc dog and dog agility. Working strains have strong herding instincts, and some individuals can be single-minded to the point of obsessiveness. Collies can compete in herding events. Border Collies are used as search dogs in mountain rescue in Britain. They are particularly useful for searching large areas of hillside and avalanche debris. H. MacInnes believed that dark coated dogs are less prone to snow blindness.
Certain types of collie (for example Rough Collies, Smooth Collies, Shetland Sheepdogs and some strains of Border Collie and other breeds) have been bred for many generations as pets and for the sport of conformation showing, not as herding dogs. All collie dog breeds have proved to be highly trainable, gentle, loyal, intelligent, and well suited as pets. Their gentleness and devotion also make them quite compatible with children. They are often more suitable as watchdogs than as guard dogs, though the individual personalities of these dogs vary.
The temperament of these breeds has been featured in literature, film, and popular television programs. The novels of Albert Payson Terhune, which were very popular in the United States during the 1920s and 1930s, celebrated the temperament and companionship of his early AKC collies. More famously, the temperament and intelligence of the Rough Collie were exaggerated to mythic proportions in the character Lassie, which has been the subject of many films, books, and television shows from 1938 to the present.
The Lassie character was featured in a book titled Lassie Come Home by Eric P. Knight. Knight's collie "Tootsie" was the inspiration for the book, which was a collection of stories based on her and other collie legends he collected from talking to friends and neighbors. One such story was most likely the documented tale of "Silverton Bobbie", the Oregon collie who crossed the US to get to his owners. While the dogs who played Lassie on-screen were from AKC lines, the actual Tootsie looked nothing like them, although she did come from a collie breeder.
Some collie breeds (especially the Rough Collie, Smooth Collie, and the Australian Shepherd) are affected by a genetic defect, a mutation within the MDR1 gene. Affected dogs are very sensitive to some drugs, such as Ivermectin, as well as to some antibiotics, opioids and steroids – over 100 drugs in total. Affected dogs also show a lower cortisol concentration than normal. The Verband für das Deutsche Hundewesen (The German Kennel Club) encourages breed clubs to test all breeding stock and avoid breeding from affected dogs.
Collies may have a genetic disease, named canine cyclic neutropenia, or grey collie syndrome. This is a stem cell disorder. Puppies with this disorder are quite often mistaken for healthy Blue Merles, even though their colour is a silver grey. Affected puppies rarely live more than 6 months. For a puppy to be affected, both the sire and the dam have to be carriers of the disorder.
Herding dogs of collie type have long been widespread in Britain, and these can be regarded as a landrace from which a number of other landraces, types, and formal breeds have been derived, both in Britain and elsewhere. Many of them are working herding dogs, but some have been bred for conformation showing and as pets, sometimes losing their working instincts in the course of selection for appearance or for a more subdued temperament.
Herding types tend to vary in appearance more than conformation and pet types, as they are bred primarily for their working ability, and appearance is thus of lower importance.
Dogs of collie type or ancestry include: