Border Collies are a highly intelligent and energetic breed of herding dog known for their remarkable agility, trainability, and work ethic. Border Collies are medium-sized dogs with a well-proportioned body. They have a double coat with a dense, weather-resistant outer coat and a soft undercoat. Coat colors can vary, with black and white being one of the most common combinations, but they can also be red and white, blue merle, and other patterns. Border Collies are renowned for their intelligence and are often considered one of the smartest dog breeds. They are alert, responsive, and eager to please. They have a strong work ethic and are known for their herding instincts. They can be loving and loyal companions but may be reserved around strangers.