The Border Collie is a working and herding dog breed developed in the Scottish borders for herding livestock, especially sheep. It was specifically bred for intelligence and obedience. It is very fetch-oriented. While black and white is the most commonly seen color pattern of the Border Collie, the breed appears in just about any color and pattern known to occur in dogs. Some border collies may also have single-color coats. Border collies require considerably more daily physical exercise and mental stimulation than many other breeds. The border collie is widely considered to be the most intelligent dog breed. Although the primary role of the border collie is to herd livestock, the breed is becoming increasingly popular as a companion animal. Other enthusiasts oppose the use of border collies as show dogs, for fear that breeding for appearance will lead to a decline in the breed's working dog traits. Few handlers of working Border Collies participate in conformation shows, as working dogs are bred to a performance standard rather than appearance standard.