The Shetland Sheepdog is a small, active, and agile herding dog standing between 13 and 16 inches at the shoulder. The long coat is harsh and straight, with a dense undercoat, and comes in black, blue merle, and sable, with white markings. The coat, along with a long, wedge-shaped head; small, three-quarter erect ears; and deep-chested, level-backed torso, give Shelties the look of a rough-coated Collie in miniature. Bright and eager Shelties are easy trainers and world-class competitors in obedience, agility, and herding trials. They are sensitive and affectionate family dogs, highly in tune with the mood of the household. They like to bark and tend to be reserved toward strangers—two qualifications of an excellent watchdog (akc.org).