The Cairn Terrier is a working breed of dog originated in the Scottish isle of Skye. It is one of the oldest terriers, probably one of the ancestor´s of the modern Terrier breeds West Highland White, Scottish and Skye. The height of the Cairn, which differs from that of other terriers, is one of the most important distinctive features of the breed, known as Cairishness. Originally used for hunting vermin among the cairns (the piles of small stones used to mark Scottish farm borders and graves), that gave the name to the breed, Cairn Terriers have shown many other talents, while keeping its terrier abilities, such as watchdogging and tracking. They also excel at obedience and agility competitions and performing tricks. Today, this delightfull little dog is mainly a family dog that does not disdain chasing any less careful rodent.The height of the Cairn, which differs from that of other terriers, is important in giving the breed the distinctive conformation that has been called "Cairishness." He is not so low to ground, in proportion to his size, as the Sealyham and the Scottish Terrier. There is one, and only one, correct size for the Cairn Terrier-14 pounds for dogs, 13 pounds for bitches, and the dogs should be in proper proportion to those weights.

The Cairn Terrier is small working terrier, very hardy, strong but not heavily built, with a fox-like expression. This peppy, very hardy little terrier has a compact, Well-muscled and strong body, with good bone structure, deep, well-sprung ribs and strong hindquarters. The front legs are moderately long and the forefeet are larger than the back feet. The back is medium length and the top line is level. The head is shorter and wider than that of any other terrier with bushy topknot and shaggy eyebrows. The skull is robust and separated from the muzzle by a definite stop. The muzzle is powerful but not heavy and the nose is black.The medium-sized eyes are deep set, rather sunken, the colour being hazel or dark hazel depending on the coat colour. The small, pointed ears are set wide apart and carried erectly. The short hairy tail is well furnished with hair but not feathery. It is carried gaily but never curled over back. The double, waterproof coat has a profuse shaggy outer coat and a soft furry undercoat. The coat comes in cream, wheaten, brindle, sand, red, blackish and various shades of gray.