Cairns were bred and used originally to work among rocks and boulders, not in flat country earth’s, though they will do so when called upon. They were also kept on farms to get rid of vermin, hunt hares, badgers, foxes, guard the family and their property. To preserve the correct type it is essential to maintain the lithe, wiry frame with enough length of leg and body to enable the terrier to jump and scramble over rocks and to turn in tight places. A compact body and strong loins are essential for stamina and jumping ability, but the back must not bee too short or stout, or the ability to turn in narrow places is lost.

A Cairn's head is very individual to the breed. In full coat it should give a general appearance of roundness when viewed from the front, with dark sparkling eyes, hazel or brown, rather deep- set and placed well apart beneath shaggy eyebrows. The ears are set high on the outside of the skull , vertical on the outer but sloping inwards on the inner edge. they should be small tightly pricked and free of long hair. The Cairn has a small head but the skull should be broad in proportion to the whole, the foreface of equal length - not longer than the skull - with a distinct but not exaggerated stop between the eyes. The jaw must be strong furnished with large teeth, meeting in a scissors bite. 

Hair on the head should be thick and profuse but not so long as to hide the dog's expression. Here a little tidying is not objected to, the art is to leave an expression of natural shagginess without too much hair. Young Cairns often tend to look too long in the jaw before the head is fully furnished, but this impression disappears with maturity and growth of coat. 

The body is covered with a double coat. The top-coat is profuse, hard and weather resistant, but not wiry. The undercoat an essential feature that should not be overlooked, is soft, close and short like fur. 

The natural manner in which Cairns are presented is carried on in the way they are handled in the ring, usually on a loose lead with the handler having some bait in hand or pocket. Cairns show themselves looking brightly up at the handler and moving freely without being strung up on a tight lead. It is not done to 'stack' a Cairn or to kneel down and hold it in position as in some other terrier breeds.

Bitches are often less keen to show off their points by not using their tails as freely as the dogs and so are more difficult to judge, but are still always shown naturally.

The whole impression given by a typical Cairn is that of a keen workmanlike but friendly gay terrier, well proportioned and balanced, active and agile, well able to look after himself when engaged in the work for which he was originally bred. Bitches have a softer sweeter expression, but prettiness or lack of substance are undesirable attributes in a typical Cairn of either sex.

In character the Cairn fits well into any kind of household suitable for a dog. It is just as happy with a town family as living in the country, provided it receives sufficient exercise and has a garden in which to give vent to it's natural instincts. By nature the breed is faithful, but with a decided streak of independence a Cairn is self-reliant and will usually find something to keep himself amused if nothing is provided. Good swimmers, they love water and hunting given the chance this can become a passion and a secure fence is a must for a breed with the Cairns background and inborn love of sport. His sharp but meaningful bark is an efficient deterrent to intruders.

Human companionship is indispensable to the Cairn's happiness. He is good with children and the ideal companion for those growing up in the country, being always ready and eager for any kind of activity that is on offer. He is sensible and kindly if treated with respect.