This smart dog cannot learn much. With the right training, Cairn can master an unlimited number of techniques and commands. However, it may be completely impossible to stop the cairn from doing what terriers love to do: chase (and dig and bark). The cairn will chase squirrels, cats, rabbits and other dogs, if possible. For this reason, he can only be walked in public places on a leash, and run free only in a securely fenced yard.