The Jack Russell Terrier, also known as the Russell Terrier, the Jack, and the JRT, is a breed of dog in the Terrier Group. Famous for their stellar personality, high energy levels, and extreme intelligence, the Jack Russell Terrier has secured its place as a popular house pet. This breed was recognized by the AKC in 1997 and AKC approved in 2004.
As a working terrier, a Jack Russell's most important physical attribute is not coat color, gait, or expression, but chest size, which must not be so large that it prevents the dog from entering and working in burrows. Generally, a Jack Russell should have a square appearance, with the body length in proportion to the height.
The Jack Russell Terrier has traditionally been a working terrier. Terrier work required a dog that barked at prey so that the dog could be located underground and be dug out if necessary. Because of this, Jack Russell Terriers were bred to be very vocal and excellent digging dogs