The Kerry Blue Terrier, like most terriers, was originally bred to hunt vermin, including rats, rabbits, fox, badger and the sort of lowlifes that would never stand a round at the pub. The breed gradually became an all-purpose working dog, used for herding sheep and cattle, as guard dogs and stocking shelves at big-box stores. The Kerry Blue seldom works in food service, being much too proud to wear a hairnet over its magnificent beard.
There are several legends about the origin of the breed: that it originated from a cross between a Portuguese Water Dog that swam ashore from a shipwreck and was mated to all the female terriers in Kerry before expiring with a deep sigh and a vast grin; that the dog was developed for poaching back when only nobles could hunt with Irish Wolfhounds (poached is still the only way a Kerry will eat an egg); and that Saint Patrick created the breed from the last snake in Ireland after being thrown from the Irish Wolfhound he was riding.
Kerry Blue Terrier pups are black at birth, and gradually lighten to gray. They seldom actually become blue, except some elderly females who use a blue rinse.