TheReal Jack Russell Terrier may be any height between 10" and 15" (at the shoulder), it may vary in coats, markings, type, and for sure personality... they are ALL real Jack Russell Terriers. There is no "ideal"... the "ideal" is what suits their owner for what they want/need to do with their terrier. That is the uniqueness of this diverse terrier. The diversity within theJRTCA breed standard is what makes the Jack Russell Terrier suitable for a variety of working and performance abilities - in contrast with the narrow, cosmetic breed standards of many show breeds.

The "Russell Terrier" and the "Parson Russell Terrier" are both variants of the Jack Russell Terrier made into "separate breeds" by the American Kennel Club (AKC). They are nothing more than variants of the original Jack Russell Terrier as always supported by the JRTCA. The JRTCA standard includes the full range of sizes needed for earth work. It is to be known our standard is to allow a terrier to follow the red fox to ground. The dog needed the drive and structure to mirror the agile intelligent fox. The Jack Russell Terrier had to be able to outsmart the fox and have the courage to do so for the handler as a team.