Personality
Everyone remembers Toto from the movie The Wizard of Oz. Spunky, curious, fearless, and loyal, little Toto went everywhere with Dorothy and helped her stop the Wicked Witch of the West and even exposed the Wizard as simply a man behind a curtain. Most Cairn Terriers are exactly like Toto – loyal to their family, curious and brave. They are excellent companions for families of all shapes and sizes and can even be useful vermin exterminators on farms.
Though they are good family dogs, small children and Cairn Terriers are not a good mix. This breed doesn't have a lot of patience and has been known to bite. Children who are too young to know when to leave a dog alone do not mix well with this breed.
Activity Requirements
Cairns don't need a lot of vigorous exercise and can happily dwell in an apartment or condominium. One daily walk and the occasional chance to get out and run in a yard or park will cover their exercise requirement . Cairns should always be kept on a leash or in a fenced in yard, as they will take off after small animals and will not respond to calls to return home.
Trainability
Like nearly all terrier breeds, the Cairn can be stubborn and willful. Training requires consistency, patience, and lots of treats. Discipline is wasted on the Cairn as they will just stop listening to you all together. They must be trained early on to understand who is in charge of the house, and that the leaders mean what they say. If a Cairn Terrier sees even one opportunity to bend the rules, they'll take it and run with it.
Behavioral Traits
Barking is the biggest complaint owners have of the Cairn. Like other terriers, Cairns bark at every noise or approaching car, bike, cat, dog, mailman or falling leaf, and usually won't stop until they are good and ready. Their bark is shrill, and can annoy nearby neighbors.
Cairns can be aggressive. People don't normally think of small breeds as aggressive, but Cairns are not patient creatures. If teased or annoyed, they will snarl, snap or bite. They are highly possessive of food and toys, and are not likely to be intimidated by larger dogs.