To be precise they are actually called Scottish Sheepdogs or Scotch Sheep Dogs.
They were first bred in the North of England. The Vikings used them to herd reindeer and they have a unique ability to hypnotize cattle and sheep. They crouch down low in front of these animals and mesmerize them with an unflinching stare. They have a natural ability to round up herds and are particularly useful to shepherds. They can be trained to answer complex  commands by whistling.
Border Collies love to work and have a great deal of energy. They need to be exercised regularly and love to be given tasks to do. They are masters at catching and fetching balls and other items.
Because of their willingness to work and their high intelligence they have been used in many other occupations. These include working with bomb and narcotics squads, the police and search and rescue. Some have been used as guide dogs and they perform very well in obedience and agility competitions.