Their only requirement is regular exercise-perhaps more than other dogs of this size. Many Cairns like to swim. The hunting instinct remains strong in this breed. Loose Cairns will take off after anything they consider quarry. They will, however, adjust to a cat in their immediate environment.
Cairns can be quite feisty and scrappy with one another.
Males in particular are territorial and they are fearless. This breed is a good companion, but not a lap dog. They love to play and enjoy children if they are also given a time to be quiet and the children don't pinch or pull tails. When alarmed or irritated, they will voice their displeasure. Overall, the Cairn terrier is one of the more healthy, long-lived breeds owners could choose.