The Jack Rat Terrier is a small dog descended from two hunting breeds: the Jack Russell Terrier, of English origin, and the Rat Terrier, an American breed that started out as a pest exterminator around farms.
The best of the breed possesses its parents' speed and topnotch hunting abilities, as well as their intelligence, trainability, and considerable level of energy.
The Jack Russell Terrier was primarily a fox-hunting dog, bred by Reverend John Russell to bolt foxes from their dens and stand out in the field in a largely white coat while holding the quarry for its master. The dog is well-balanced in body, with legs long enough to keep up with larger hunt hounds, yet the chest not to deep to be able to delve into foxholes. The prey drive is high, and indoor living is not really suited to them because of their need for wide open space and vigorous activity.
The Rat Terrier is prized for its speed and agility in the field, and warm, gentle disposition whenever indoors with a family. Its ancestors were most probably "pit" dogs used in ratting or rat-baiting, a common preoccupation among British gamblers in the early 19th century. Modern day Rat Terriers can be relied on to rid a household or farm of vermin, and also be a loyal companion on hunts for small game.
