Jack Russel Terrier

Breed At A Glance


Playful, perky and fearless

Life Expectancy
15+ years

Average Height
10-15 inches

Average Weight
14-18 lbs

Coat Color
White with tan, black, or brown markings

Coat Length/Texture
Short and smooth, rough or broken

Shedding Propensity
Consistent year-round

Also known as Fox Terrier, JRT and “Jack”

General Temperament

The spirited and courageous Jack Russell Terrier is well-known for it’s energetic and playful nature. They are a curious, amusing and amazingly confident breed. Most people can recall the sight of this tiny little Terrier jumping several feet straight up in the air. The JRT is devoted to it’s owners and territory, and will bark vigorously to warn of approaching visitors. This breed maintains it’s original hunting nature and is usually a strong contender in earthdog trials.

Jack Russells are usually excellent companions for active children, as long as kids are taught to not tease or hit the dog. The Jack Russell Terrier is known for it’s unwillingness to back down in a fight. This can get the dog into serious trouble when challenging larger or more aggressive dogs; in fact, many have been killed in dog fights or sustained injuries significant enough to require euthanization. Extensive socialization with other dogs is required for this breed to minimize potential problems with this “Napoleon Complex.” And due to their strong hunting instinct, they should never be trusted with smaller household animals such as cats, rabbits or birds.

Jack Russells love to dig and explore. Due to their high level of energy, they will generally be happiest in a house with at least a small yard, although if sufficiently exercised, they can function well in an apartment. In addition to it’s love of jumping and digging, the Jack Russell Terrier is also an excellent climber; therefore any enclosure in which the dog is allowed to run free should have a tall fence and that is also buried deeply into the ground. They will get bored and destructive if not given enough activity, and as such are not well-suited for a sedentary household.

Training a Jack Russell Terrier can be a bit more difficult that some other breeds, despite the fact that they are very intelligent and love their owners. They simply have a mind of their own and don’t always feel like following instructions. The most symbiotic relationship will be with an owner who is strong-willed and consistent, otherwise this “little dog in a big dog’s body” will take over and rule the house.

Breed History

The name “Jack Russell Terrier” is an homage to the Reverend John Russell, an English parson born in 1795. In the first half of the 19th century, Russell purchased a small white and tan Terrier from the local milk man. He used this dog as the foundation for a line of Terriers that were highly energetic and courageous in the sport of fox hunting without the aggression that would serve to the harm the game. These dogs were lower to the ground than the standard Fox Terriers at the time and could be easily handled with average-sized hands and human power while on the hunt. Although it is unlikely that any of the dogs currently referred to as Jack Russell Terriers (or JRT’s) can be linked back to Parson Russell’s original Terriers, his principles serve as the standard for modern JRT’s in general appearance and, more importantly, functionality.

Jack Russell Terrier vs. Parson Russell Terrier vs. Russell Terrier:

A series of changes to the breed status has confused and confounded dog enthusiasts for the past few years. This appears to be an issue largely of ideology. Historically, breed registries throughout the world recognized the Jack Russell Terrier as the lower and longer version of the dog, while the taller and more squared version was known as the Parson Russell Terrier. In 2000, the Jack Russell Terrier was approved for registration by the American Kennel Club without the support of the breed’s largest registry club, the Jack Russell Terrier Club of America (JRTCA, established in 1976). The JRTCA bases it’s dogma on that of the Jack Russell Terrier United World Federation (JRTUWF), focusing more on functionality of the breed than meeting a specific narrow set of conformation standards. Essentially, this is a difference between promoting field types versus show types. In fact, the JRTCA is strongly opposed to kennel club registrations in general, as they believe this leads to creating dogs that conform to a certain physical standard without regard to the breed’s natural working ability, subsequently jeopardizing the overall health of the breed in the process. This difference in philosophy lead the JRTCA to petition the AKC for the removal of the Jack Russell Terrier from their registry. The AKC responded by combining Jack Russell and Parson Russell as the same breed in 2003.

The “Russell Terrier” is considered a separate breed by the AKC, and is currently a part of their Foundation Stock Service. This breed was derived from the Parson/Jack Russell Terrier, but began to be differentiated in Australia in the 1960’s. The Russell Terrier is, in essence, a shorter version of the breed, reaching a maximum of 12 inches tall.

Body Structure and Composition

The most important physical characteristic of the Jack Russell Terrier is the size of the chest, which should not be too large to prevent the dog from chasing its quarry into a hole. According to the Jack Russell Terrier Club of America, dogs considered to be Jack Russells should be between 10 and 15 inches tall with a body that is in proportion to it’s height. The muzzle should be slightly shorter than the length of the skull, although this breed is not considered brachycephalic (“snub-nosed”). The muscular neck leads down to a straight back. The tail is short and stout, just long and strong enough for a handler to get a good hold of it to pull the dog out of a hole. The coat can be smooth, rough or broken.

Medical Information

The Jack Russell Terrier, as defined by the JRTCA, is a relatively healthy and long-lived breed due to a wide gene pool and lack of inbreeding. But, due to the breed’s recent increase in popularity over the last 10 years, some lines have developed some hereditary health issues.

Some of the most prevalent problems facing Jack Russell Terriers are related to the dog’s eyes, including hereditary cataracts and Primary Lens Luxation (PLL). PLL occurs when the lens moves out of place, causing sudden and intense pain, followed by blindness quickly thereafter. The condition must be corrected by surgery quickly, otherwise the blindness will become permanent.

Patellar Luxation (or “slipped stifle”) is a condition sometimes experienced by the Jack Russell Terrier, and occurs when the knee-like joint above the hock slips out of place, often requiring surgery. Another disease called Legg-Calve-Perthes Disease (LCP) affects some Jack Russell lines. LCP results when the blood supply to the head of the femur is interrupted, resulting in the death of the bone cells. This condition often repairs itself in time, but can lead to stiffness in pain. The Jack Russell Terrier can also suffer from lack of motor coordination caused primarily by two different conditions, Ataxia and Myasthenia Gravis. Ataxia is a general term for severe incoordination of movements, suggesting neurological dysfunction, most notably in the cerebellum. Myasthenia Gravis is a autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatigue. Dogs that show symptoms of any of these four diseases should not be bred.

On occasion, male Jack Russell Terriers are born with Cryptorchidism, a disorder in which either one (unilateral) or both (bilateral) testes remain undescended after birth. A unilaterally chryptorchid male is less fertile than a normal male, and should not be mated. A bilaterally chryptorchid male is infertile.

Congenital deafness can also afflict some Jack Russell Terrier lines. The Brainstem Auditory Evoked Response (BAER) test is available to puppies over 5 weeks of age, and responsible breeders should have this test performed on all puppies that are to be sold.

All coat types of the Jack Russell Terrier are easy to care for: a simple periodic brushing will do the trick. Dogs that are to be shown should be hand-stripped (i.e. dead or loose hairs should be pulled out individually by a professional groomer).

Anecdotal Information

The Jack Russell’s fearlessness in the face of danger has been well documented for years. In 2007, a JRT in New Zealand reportedly saved the lives of five children from an attack by two pit bulls. He apparently charged the other two dogs and kept them at bay long enough for the kids to get away, and subsequently had to be euthanized after sustaining massive injuries. “George” was posthumously awarded a medal of bravery by the SPCA, and a former U.S. Marine donated his Purple Heart to George’s owner.

The character of Eddie in the television show Frazier was played by two Jack Russell Terriers named Moose and Enzo (Moose’s son). The two also appeared in the film My Dog Skip.

The character of Milo in the film The Mask was played by a Jack Russell, as was the character of Nippy in Problem Child 2.

In the PBS children’s television show Wishbone, the title character was a Jack Russell Terrier who often daydreamed of being the lead in classic works of literature.

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