The breed was derived from Jack Russell's working terrier strains that were used in the 19th century for fox hunting.

The only requisite was color, the instinct combined with the will to employ earth-work, and the size to work efficiently underground.

It was in the country of development, Australia, that this 10-12 inch dog was first standardized by Kennel Club recognition with the official name "Jack Russell Terrier" applied to the breed.

[1] This ultimately led to recognition of the breed by FCI (Fédération Cynologique Internationale) countries, including Ireland and most recently, the US.

They are bred by dedicated fanciers to preserve their working functional conformation and the instinct to employ their original purpose as earth terriers.

This makes them an excellent performance breed participating in a variety of events: natural hunting which includes earthwork, agility, rally, obedience, tracking, go-to-ground, and conformation, etc.

In 2009 the UKC changed the name to Jack Russell to go back to their original standard and align themselves with the rest of the world.

A 2014 study identified the KCNJ10 gene as being responsible for the spinocerebellar ataxia accompanied by myokymia and/or seizures in the breed.