The Border Collie is a British breed of herding dog of medium size. They are descended from landrace sheepdogs once found all over the British Isles, but became standardized in the Anglo-Scottish border region. Presently they are used primarily as working dogs to herd livestock, specifically sheep.The Border Collie is considered a highly intelligent, extremely energetic, acrobatic and athletic dog. They frequently compete with great success in sheepdog trials and a range of dog sports like dog obedience, disc dog, herding and dog agility. They are one of the most intelligent breed of all domestic dog breeds. Border Collies continue to be employed in their traditional work of herding livestock throughout the world and are kept as pets.