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Jack Russell Terrier

The Jack Russell Terrier was originally developed in 19th century England by a clergyman named Jack Russell. The resultant spirited little terrier was used to hunt small game by digging the prey out of its den, particularly foxes. Breeders have traditionally focused a great deal on the Jack Russell’s working ability, so the standard is very broad but realistically falling into a wide range of accepted body types. On English hunts, the Jack Russell Terriers were supposed to be long-legged enough to keep pace with the hounds. The energetic and playful Jack Russell is known for being a fun family companion. Some of the Jack Russell’s special talents include hunting and agility.

Jack Russell Terriers are tough and sturdy little dogs. The body length typically is proportional to the height, and presents a compact, well muscled and balanced appearance. The head is in proportion to the body. The skull is flat, of moderate width at the ears, and narrowing to the eyes. There should be a defined stop but not overly pronounced. The length of the muzzle from the nose to the stop should be slightly shorter than the distance from the stop to the occiput (the small bone of muscle insertion at the back of the skull. The nose is typically black. The jaw is powerful, densely bones, and well muscled. The eyes are almond shaped, dark brown in color and convey a high intelligence. The ears are small to medium shaped drop ears carried forward close to the head and of medium thickness. Two bites are acceptable, level and scissor, The neck is muscular, of moderate length, and gradually widens at the shoulders. The shoulders are sloping, strongly muscled and clearly defined at the withers. The forelegs are thickly muscled and straight boned with joints in correct alignment (outward curving at the wrists – called carpal valgus – is often seen, but is not an acceptable breed trait). Elbows are perpendicular to the body and work free from the sides. The chest is medium to shallow, medium to narrow, with the front legs not oriented very far apart, imparting an athletic, as opposed to a heavy or deep chested appearance. The back is muscular, and of medium width in comparison to the height of the terrier, offering a balanced look. The loin is slightly arched. The hindquarters are well muscled offering a great deal of drive and power. Looking from behind, the hocks should be straight and not bowed outward. The tail is set rather high, carried gaily and in a length proportional to body length (usually about four inches long). The coat is smooth and of medium thickness, offering reasonable protection from the elements and undergrowth. Rough or broken coated, without being woolly. The main color is white (more than 50% white) with tan, black, or brown markings. The gait is well coordinate between front and rear limbs, with a straight, non-bouncy appearance. An Irish-type called Jack Russell, called Shortys, have shorter legs than the English-type, but some consider this trait just a normal breed variation.

The Jack Russell Terrier is an active, happy, loyal, and loving dog. Spirited, intelligent, and obedient, they are also utterly fearless. A breed that loves to engage in play, they love their toys. Stable Jack Russells are friendly and tolerant of children, but not raised with leadership and obedience to instill confidence, some Jack Russells can be intolerant and even dangerous around small children. If you let Jack Russells to take an inch, they can become very willful and impassioned to take a mile. For this reason it is essential that you are this dogs pack leader. The Jack Russell Terrier needs to be given rules to follow, with limitations clearly set as to what he is and is not allowed to do. It is important not to let this little dog fall into “little dog syndrome,” where he believes he is pack leader dominant to all humans. This is where varying degrees of behavior problems will arise, including guarding, snapping, and obsessive/compulsive barking to name a few.

Jack Russell Terrier

Jack Russell Terriers are highly trainable, able to perform impressive tricks, as is evidence in their being commonly used in TV and movies. However, if you do not show unquestionable authority over the dog, they can be difficult to train, responding best to a firm, experienced trainer. Jack Russells who have been allowed to take over are known to exhibit aggressive toward other dogs, fighting to the death in severe cases. As such, frequent socialization with other dogs and people from a young age is very helpful.

Jack Russell Terriers have strong hunting instincts and therefore should not be trusted with other small animals. They like to chase, explore, and wander, so they should not be left off their leash unless very well trained. Jack Russells like to bark and dig and tend to get restless and destructive if not kept frequently occupied and well exercised. Jack Russells are also known to be climbers, which means they are known to scale fences. They are also incredible jumpers. Most Jack Russells have little trouble jumping 5 feet on more.

Jack Russell Terriers are not an ideal breed for inexperienced dog owners. The owner needs to be as strong-willed and consistent, or these little dogs will take over. With the right owner, the Jack Russells can live very fulfilling lives and offer wonderful, spirited companionship, but is not recommended for those who do not fully grasp what it means to be the dog’s pack leader. Nervousness, extreme feafulness, or over-aggressiveness are often the result of an improperly raise Jack Russell Terrier.

Height: 10-15 inches

Weight: 15-20 pounds

Inherited health problems known this breed are medially luxating patella, progressive retinal atrophy, deafness, and Legg Perthes disease.

Jack Russell Terrier will do okay in an apartment if it is sufficiently exercised, but tend to be very active indoors.

They do best in an average sized yard or larger, preferably fenced in given their tendency to explore and wander.

Jack Russells need regular exercise regardless of living conditions, with at least one long brisk walk per day, and ideally ample time each day to open his legs and run in an open space. They can become quite the nuisance if not exercised adequately.

All coat types are easy to groom by combing and brushing regularly with a firm bristle brush, with bathing only done on an as needed basis.


Roger L. Welton, DVM

Founder and Chief Editor,

President, Maybeck Animal Hospital


Article updated 11/11/2012

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