The Collie is not a specific breed but is a distinctive type of herding dog, including many related landraces and formal breeds. It originates in Scotland and Northern England. It is a medium-sized, fairly lightly built dog with a pointed snout, and many types have a distinctive white pattern over the shoulders. Collies are very active and agile, and most types have a very strong herding instinct. The collie type has spread through many parts of the world (especially Australia and North America) and has diversified into many varieties, sometimes with mixture from other dog types. Some of the collie types have remained as working dogs, used 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. Collies are generally medium-sized dogs of about 10 to 25 kg (22 to 55 lb), fairly lightly built with a pointed snout and erect or partly erect ears, giving a foxy impression. Cattle-herding types tend to be rather more stocky. The fur may be short, flat, or long, and the tail may be smooth, feathered, or bushy. Collies have a moderately long tail, with the end of the bone reaching to the hock or joint below. When the dog is quiet, then the tail is low, and has a upward swirl or twist. Types vary in colouration, with the usual base colours being black, black-and-tan, red, red-and-tan, or sable. Many types have white along with the main colour, usually under the belly and chest, over the shoulders, and on parts of the face and legs, but sometimes leaving only the head coloured – or white may be absent or limited to the chest and toes (as in the Australian Kelpie). Merle colouration may also be present over any of the other colour combinations, even in landrace types. The most widespread patterns in many types are black-and-white or tricolour (black-and-tan and white).