This is a working terrier, and it should be hardy, game and active. It is short-legged, and longer than it is tall, but not as low to the ground as the Sealyham or Scottish terriers. Its build enables it to fit into close quarters in pursuit of its quarry. Its head is shorter and wider than any other terrier, giving it good jaw strength. Its weather-resistant coat consists of a soft, close undercoat and a profuse, harsh outer coat. Furnishing around the face adds to its somewhat foxy expression.

The Cairn Terrier is the essence of terrier; plucky, spirited, bold, inquisitive, hardy, clever, stubborn and scrappy. It is responsive to its owner’s wishes, however, and tries to please; in fact, it is surprisingly sensitive. This breed can be a good house pet as long as it is given daily physical and mental exercise in a safe area. It enjoys playing with children and is tough enough to withstand some roughhousing. It can be aggressive with other dogs and chases small animals; it loves to sniff, explore and hunt. It digs; some bark.