How To Tell If You Have A Purebred Jack Russell Terrier

It is important to remember the presence or absence of registration papers does not change the DNA inside a dog. They can be purebred without having papers and unfortunately, in some cases, they can have papers without being purebred.

Maybe you acquired your Jack Russell Terrier from a backyard breeder, or pet shop, or a newspaper ad and you are wanting to know if they are purebred?

Perhaps you purchased a Jack Russell Terrier with registration papers and something about your terrier does not look right, so you are wondering if they really are purebred?

In both instances it can be a good idea to find out whether your Jack Russell Terrier is purebred. The most definitive way to do this is to have their DNA tested. Conveniently, you can purchase DNA testing kits that allow you to test you Jack Russell Terrier’s genes yourself with no vet visit and no blood tests. A simple Google search will help you in finding these kits.

Testing your Jack Russell Terrier’s DNA is not however always possible, and it can be helpful if you know certain physical characteristics and personality traits to look for that will help you correctly identify a purebred dog.

Table of Contents

Physical Characteristics of a Purebred Jack Russell Terrier

There are several key elements/areas to observe in a Jack Russell Terrier to assist in determining whether it is purebred. These are:

General appearance
Head, Neck and Facial Features
Forequarters

Hindquarters and Tail
Coat and Colour

General Appearance

A purebred Jack Russell Terrier has a sturdy, rectangular shaped body. The body length of a Jack Russell Terrier needs to be longer than its height, and according to The Jack Russell Terrier Club of America, they should measure between 10 and 15 inches heigh at the shoulder.

The height of a Jack Russell Terrier should present a balanced image and their back should be strong and straight and should be slightly arched at the loin. The loin is located between the end of the rib cage and the beginning of the pelvic bone.

A Jack Russell Terrier’s weight should be proportionate to the size of their head and the length of their body and should generally be between 14 and 18 pounds (6 to 8kg).

These tough terriers are forward always moving and very much on their toes. They should move freely, be lively, and well-coordinated with a straight leg action in their front and back. Their feet should be round shaped, have hard pads and should point forward and not turn in nor out.

Head, Neck and Facial Features

A Jack Russell Terrier’s head should be slightly flat and of moderate width between the ears, tapering down to the eyes.

The stop should be noticeable but not overpronounced. The ‘stop’ is that spot on the Jack Russell Terrier’s head where the muzzle and forehead meet, the imaginary dividing ‘line’ so to speak. The measurement of a Jack Russell Terriers muzzle from the nose to the stop should be slightly shorter than the length from the stop to the occiput (the back of the head).

They should have a black nose and well boned, strong muscled cheeks. Their teeth should be straight and when closed be in a scissor bite. A scissor bite means the upper teeth are slightly overlapping the lower teeth.

A Jack Russell Terrier’s eyes should be bright, full of life, dark in colour and almond shaped.

The ears should be of moderate thickness and carried forward close to the head in “V” shape. When alert, the tip of the “V” should not extend past the outer corner of the Jack Russell Terrier’s eyes.

It is important to look for a well-muscled, proportionally long neck that broadens at the shoulders.

Forequarters

The forequarters consist of the withers (shoulder blades), shoulders, front legs, and chest.

In purebred Jack Russell Terriers, the slope down from the top of the withers to the shoulders should gradually widen and the measurement between the shoulders should be between 10 and 15 inches (25 to 38cm). The shoulder area should be muscular, of good length and be laid back.

The Jack Russell Terrier was originally bred to hunt foxes in burrows which meant it needed to fit through narrow spaces. This is present in the breeding today because a purebred Jack Russell Terrier’s chest should be fairly narrow and the front legs not too wide apart. As a guide, someone with average sized hands should be able to wrap their hands around the chest (one on each side) behind the shoulders.

The forelegs should be strong and straight boned with joints in correct alignment when viewed from either the front or the side. Some Jack Russell Terriers suffer from Achondroplasia, which causes the front legs to become bowed, eventually affecting their mobility if not treated. The elbows should hang perpendicular to the body and away from the sides.

Hindquarters and Tail

A purebred Jack Russell Terrier’s hindlegs should have pronounced contours and be strong and muscular with good angulation (the angles at which the pelvis and long bones meet when the dog is standing) and bend of the stifle (the joint in the hind limbs). These features were highly valued as they helped provide explosive movements when the terrier needed to run.

From behind, the hocks must be straight and low set.

The tail should be strong, high set and in proportion to the Jack Russell Terrier’s length. It needed to be strong because Jack Russell Terriers were used to fetch foxes from holes, and the owner often had to pull their terrier out by the tail. The somewhat controversial practice of docking the tail was done to provide a sufficient handhold for gripping the terrier by the tail while in the hole.

Coat and Color

The colour of a purebred Jack Russell Terrier should be a minimum of 51% white with the remaining colour consisting of tan or black, or both. The tan or black colours should predominantly be near the base of its tail and on its face. The skin under the coat is needs to be pink with black or brown freckles in certain areas, like the stomach.

The hair on a smooth coat Jack Russell Terrier needs to be smooth, without being sparse so that it offers a certain amount of protection from the elements. The length of the fur on a smooth haired Jack Russell Terrier should be about 1.5cm long.

The hair on a broken coat Jack Russell Terrier is very similar to that of a smooth coat but it has trace hair on the head, face, legs, or body. These areas have longer, wispy hairs. A broken coat should feel wiry and not be soft as it provides protection from the elements.

The hair on a rough coat Jack Russell Terrier has excess trace hair on the head, face, legs, or body. It is longer than on a smooth or broken coat but does not exceed 10cm in length. The fur should not be soft or woolly and like the broken coat, it should feel wiry to provide protection to the terrier.

Personality

Jack Russell Terriers are high energy dogs that require adequate exercise and stimulation. If not properly socialized and stimulated, they can be aggressive towards other animals and humans, and they tend to bore easily and can become destructive.

They are known for their intelligence and their strong desire to hunt. They were originally bred in England about 300 years ago to hunt to retrieve foxes from their dens.

Jack Russell’s tend to be very loyal and protective of their owners, which makes them great guard dogs and any threat towards their territory, like the addition of a new dog, can be highly unwelcomed and in response they could seek to dominate. Jack Russell Terriers will also instinctively bark in a protective manner when approached by both people and other dogs.