The Cairn was originally from Scotland where he helped the farmers rid their farms of badgers and foxes.  They chased them from "cairns" which were piles of rocks.  Cairns are also known as "earthdogs" because they dig in the dirt and love to burrow in the rocks.  According to popular belief, the Cairn Terrier is the oldest of the short legged terriers.  It is the foundation for the other terriers such as the Scottish Terrier and the West Highland Terrier.  This dog has two coats.  The outside coat is harsh and weather resistent.  This was to keep them dry while outside and hunting vermin.  The undercoat is soft.  This dog is very sturdy, considered non-shedding, very loving and a great family dog.  He does like to bark somewhat like all Terriers.  He is somewhat stubborn so obedience class is recommended.  
To keep his harsh coat, stripping is advised.  This is a matter of pulling out the dead hair.  

For more information on Cairns, go to the Cairn Terrier of America Club website: www.cairnterrier.org