Official ICCF Breed Description
Brief Historical Overview
The Jack Russell Terrier breed was developed in the 19th century in England by Reverend John (Jack) Russell, a passionate fox hunter. His goal was to create a compact, hardy, and fearless earth dog capable of pursuing game underground and working alongside hounds. The foundation of the breed included English Fox Terriers and local hunting terriers. Over time, the breed divided into two varieties—the taller Parson Russell Terrier and the shorter, more compact Jack Russell Terrier. The modern Jack Russell combines energy, intelligence, and friendliness, retaining the endurance, courage, and agility of a true hunting terrier while becoming a beloved companion worldwide.
General Appearance
The Jack Russell Terrier is a small, well-proportioned, sturdy, and agile dog with a flexible body and lively, energetic expression. The body is slightly longer than tall, allowing freedom of movement and maneuverability. The head is proportionate to the body, with a strong muzzle tapering moderately toward the nose. Eyes are dark, intelligent, and expressive. Ears are V-shaped, semi-dropped, giving an alert look. Limbs are straight and strong with elastic paws. The coat may be smooth, rough, or broken, but must be dense and protective. The tail is set high and carried upright in motion. The Jack Russell gives an impression of an active, confident, and well-balanced dog with a distinct hunting temperament.
Important Proportions
The Jack Russell Terrier has harmonious proportions combining strength, flexibility, and mobility. Height at the withers is typically 25–30 cm, with the body length slightly exceeding the height, forming a slightly elongated outline. Weight is proportional to height—approximately 1 kg for every 5 cm of height. The head is proportionate to the body, with the muzzle length roughly equal to the skull length. The chest is deep but not broad; the circumference behind the elbows should equal twice the foreleg length from elbow to ground. Straight limbs with strong bone provide stability and endurance. All proportions emphasize compactness, balance, and working quality typical of an active hunting terrier.
Behavior and Temperament
The Jack Russell Terrier is energetic, brave, and friendly, with a vivid temperament and lively intelligence. Balanced and loyal to its owner, it is also independent and very active. It combines hunting instincts with a cheerful, optimistic character. Always ready for action, games, and work, the Jack Russell shows persistence and stamina. Intelligent and trainable, it requires consistency and attention. It is affectionate toward people, excellent with children, and endowed with curiosity and humor. Aggression and timidity are unacceptable. The Jack Russell is a lively spirit with a courageous heart, a faithful friend, and an energetic human companion.
Head
The head of the Jack Russell Terrier is proportionate to the body, with clear lines and an expression of intelligence and determination. The skull is flat, moderately broad, with a smooth stop. The muzzle is strong, tapering slightly toward the black nose, but not pointed. Lips are tight and dry. Cheeks are not prominent, giving a neat profile. The bite is scissor-shaped, jaws strong, with a full set of teeth. Eyes are almond-shaped, dark, and attentive. The head should balance lightness and strength, emphasizing the breed’s energetic and intelligent nature.
Foreface
The foreface of the Jack Russell Terrier is compact, strong, and expressive. The muzzle is moderately long and straight, tapering smoothly toward the black nose. The nose is always black, with well-developed nostrils. Lips are fine, tight, and dry. Jaws are powerful and equal in length with a correct scissor bite. The chin is defined but not coarse. Cheeks are flat, with tight skin. The face reflects alertness and determination. All features emphasize the terrier’s active, intelligent, and friendly expression.
Eyes
The eyes are dark, almond-shaped, and of medium size, set moderately deep and wide apart. The expression is bright, intelligent, and alert, showing confidence and curiosity. Eyelids are dark and tight. Light, round, or protruding eyes are faults, as they spoil the typical expression. Proper eye shape and placement give a cheerful, friendly, and slightly mischievous look, characteristic of the breed.
Ears
The ears are small, V-shaped, thin, folding forward, and lying close to the cheeks. Set moderately high, they give the dog an alert, lively appearance. When attentive, the ears rise slightly at the base, keeping the fold. Erect, oversized, or overly tight ears are faults. The skin is thin and elastic, covered with short hair. Correct ear shape enhances the Jack Russell’s intelligent, active, and confident expression.
Neck
The neck is of medium length, dry, strong, and muscular, widening toward the shoulders. Set high with a gentle arch, it gives the dog a proud and balanced appearance. The skin is tight, without folds or dewlap. The neck should be long enough to allow free head movement and maintain body harmony. Correct shape highlights the breed’s strength, elegance, and active character.
Body
The body is strong, compact, and flexible, giving an impression of power and agility. The back is straight and firm, with well-developed muscles. The chest is deep but not broad, ribs springing moderately. The loin is short, strong, slightly arched. The croup is broad and slightly sloping, with the tail set at back level. The belly is slightly tucked up, forming a sporty outline. The whole structure conveys endurance and readiness for movement.
Tail
The tail is set high, strong at the base, straight, carried upright or slightly curved when in motion. At rest, it hangs naturally. Traditionally docked to a moderate length, though a natural tail is acceptable if balanced. Tails curled over the back or too low set are faults. The coat is dense and smooth. The tail complements the confident, energetic silhouette.
Forequarters
The forelegs are straight, strong, and well-developed, providing support and power. Shoulders are long, sloping, and close-fitting. Elbows are directed backward, neither tight nor turned out. Forearms are straight with solid bone. Pasterns are short and resilient. Feet are compact and round with firm pads. Proper structure ensures free, efficient movement and endurance.
Hindquarters
The hind legs are strong, muscular, and well-balanced, providing drive and stability. Thighs are long and powerful. Stifles are well bent, hocks low and firm, directed straight back. Metatarsi are short and vertical. Feet are compact and round. Correct structure ensures ease, strength, and stamina.
Gait and Movement
Movement is free, light, and energetic, with strong rear drive and confident front reach. The motion is straight and balanced without rolling or crossing. The back remains firm, head carried high, and tail raised, showing confidence. Gait should be natural, rhythmic, and effortless. Stiff or uncoordinated movement is a fault. Proper gait reflects the breed’s strength, agility, and working vigor.
Coat
The coat may be smooth, rough, or broken. In all types, it must be dense, close-fitting, and weatherproof. Undercoat is soft and thick. Rough and broken coats may have light furnishings on muzzle and brows; smooth coats are short and glossy. Sparse, soft, or curly coats are faults. The coat must preserve natural protection and working resilience.
Permitted Colors
The base color is white, with markings in tan, black, or tricolor. White must predominate (at least 51%). Tan shades range from pale cream to rich chestnut. Black markings must be clear and even. Tricolor combinations (white, black, tan) are allowed. Blue, liver, brindle, or diluted colors are disqualifying. Correct coloring enhances expression and vitality.
Size
A small, compact, and well-balanced dog. Height 25–30 cm, slightly longer than tall. Weight 5–6 kg, proportionate to height. Bone strong but not heavy, muscles firm and dry. The build must balance strength, flexibility, and mobility. Overly light or coarse dogs are undesirable. The Jack Russell should appear athletic, energetic, and durable.
Faults
Faults include any deviations from the standard affecting balance or type: weak bone, overly long or short body, narrow chest, soft back, poor angulation, light or round eyes, incorrect ear set, sparse coat, or uneven coloring. Behavior faults include shyness, excitability, aggression, or apathy. All defects reducing balance, energy, or working ability lower evaluation.
Disqualifications
Disqualifying faults include incorrect bite (overshot, undershot), jaw deformities, blue or heterochromatic eyes, lack of nose pigment, crooked limbs, weak back, excessive or insufficient size, incorrect movement, or disallowed colors (solid black, brindle, liver, or insufficient white). Fearful, aggressive, or unmanageable dogs are also disqualified. Only ICCF-registered dogs with verified pedigrees may participate in shows or breeding.
Important Notes
Evaluation focuses on proportional balance, strong body, correct coat, and lively temperament. The dog must be agile, enduring, and even-tempered, without signs of coarseness or weakness. Natural working qualities—agility, strength, flexibility, readiness for action—are essential. White coloration predominance and harmony of physical and behavioral traits are highly valued. Only ICCF-documented dogs confirming pure origin and standard compliance are eligible for breeding and shows.
Conclusion
The Jack Russell Terrier is an energetic, brave, and intelligent breed combining compactness, strength, and a lively temperament. Loyal, active, and friendly, it retains hunting instincts with a balanced character. Thanks to its endurance, agility, and cleverness, it excels both as a working dog and as a companion. It must be well-built, active, and confident. Only ICCF-registered dogs verifying pedigree and standard conformity are accepted. The Jack Russell embodies energy, devotion, and joyful spirit.
