Jack Russel Terrier, todays dog breed

The Jack Russell Terrier is a type or landrace of small, principally white-bodied, smooth or rough-coated terrier that has its origins in fox hunting. The name "Jack Russell" has been used to describe a wide array of small white terriers, but is now most commonly used to describe a working terrier.
The Jack Russell Terrier is not the same as a Parson Russell Terrier, which is a breed recently created by narrowing the Jack Russell standard. The Parson Russell Terrier is primarily a show dog, and is rarely found in the hunt field.
The Jack Russell Terrier is also not the same thing as an Australian Jack Russell Terrier or Russell Terrier, which are dogs first brought into the Federation Cynologique Internationale (FCI) in 2000 and the United Kennel Club in 2001, and which are maintained under a different breed standard and described as having been developed in Australia out of dogs originating in England. The Jack Russell is a working terrier. Terrier work requires a dog that will bark at prey so that the dog can be located underground and be dug out if necessary. Because of this, Jack Russell Terriers were bred to be very vocal dogs.
Jack Russell Terriers are also very intelligent, high-energy dogs – requirements of a working dog which must problem-solve in the field and work tirelessly against often formidable quarry. Due to their compact size, friendly and inquisitive nature, and intelligence, Jack Russells are popular as pets. Prospective buyers should be aware, however, that while these dogs may enjoy sitting in a lap, they are not “lap dogs” – they are dogs that require training and regular and consistent exercise to maintain their temperament and to occupy their minds.