General Appearance: Medium-sized dog, slender, well balanced, with firm but not too heavy structure, body square appearance with clean curved lines that distinguish him from the smooth Fox Terrier with square lines.
Behavior/Temperament: Restless, alert, active and keen; friendly and gentle to friends, suspicious of strangers.
Head: Viewed from the top, the head is triangular in shape, broad at its base, with ears well apart, narrowing notably from the eyes to the nose tip. Viewed in profile, the upper line rises slightly from the tip of the nose to the stop, sharply between the eyes and continues to the occipital bone with a slight convexity.
- Skull: Round with moderately flat forehead. Its side lines, seen from the top, converge to the eyes. The distance from the external eye-corner to the attachment of the ears is equal to the distance between two external eye corners. Mediofrontal groove well developed.
- Stop: well developed.
- Nose: moderately developed, dark colored with wide nostrils.
- Muzzle: viewed from the top, it describes an isosceles triangle from both external eye corners to the tip of the nose; strong and well chiseled under the eyes with a sloping root of muzzle, accentuating the stop.
- Lips: dry, tight, the upper lip just over the lower, covering the teeth, allowing the mouth to close completely.
- Cheek: dry, well developed.
- Teeth: 42 teeth, regularly set and well developed, scissors bite.
- Eyes: set halfway from the occipital protuberance to the nose tip, well apart, the distance between two external eye corners being equal to the distance from the external eye corner to the nose tip. Looking straight forward, moderately prominent, large with slightly accentuated eyebrows. Roundish, well opened, alive, with a keen expression; as dark as possible. The blue variety has bluish gray; the brown variety brown, green or blue eyes.
- Ears: Set on laterally, in line with the eyes, well apart from each other and leaving good space for the skull. Triangular shaped with pointed tips, carried half-pricked, with folded tip pointing to the external eye corner. Ears are not cropped.
Neck: Of moderate length, well balanced in relation with the head, harmoniously set to head and trunk. Clean, dry; upper line slightly curved.
Body: Well balanced, not too heavy, square appearance with clean curved lines.
- Withers: Well pronounced and harmoniously connected to the front legs.
- Top line: Firm and straight, going slightly upwards from the withers to the croup.
- Back: Relatively short and well muscled.
- Loin: Short and firm, harmoniously connected to the croup.
- Fore chest: Not very pronounced, moderately broad, allowing free movement of the forelegs.
- Chest: Long and deep, reaching to level of the elbows. Sternum long with well arched ribs; being horizontal, the sternum is moderately curved.
- Underline and belly: Slightly curved, rising to the rear but no whippet-like tuck up.
Tail: Low set, short, docked at the joint between the second and third caudal vertebrae (natural tail: short, not reaching the hocks, low set, of good strength, carried gaily, not curled over the back).
- Forequarters: Viewed from the front, straight, moderately apart, but in line with the hind legs, which are also straight, but move apart.
- Shoulders: Long, bent in a 110 degree to 120 degree angle.
- Upper arms: Approximately the same length as the shoulder blade.
- Elbows: Set tightly to the body, at the same time level as the chest underline.
- Carpal joints (carpi, wrists): Open angle.
- Pasterns: Straight and thin.
- Forefeet: tight, neither turned in nor out; hare feet: the two median toes are longer.
- Hindquarters: Strongly muscled, well developed thighs, legs in proportion to the thighs, high set hocks with obtuse angles.
- Upper thighs: well developed and muscled.
- Stifles: obtuse angulation.
- Lower thighs: in proportion to the size of the upper thighs.
- Hocks: High, obtuse angulation.
- Metatarsi (rear pasterns): Straight
- Hind feet: tight, longer than the forefeet
Gait/Movement: elegant, free, short and quick movement.
Skin: Well applied, not loose. Dry.
Coat hair: short haired, smooth, thin but not soft, laid close to the skin, in the type of rat's hair. One cannot see the skin through it. Thinner on the head, ears, under the neck, on the inner and lower parts of the forequarters and backs of the thighs.
Color: Ground color predominately white with black, blue, or brown markings; the following typical and characteristic markings must always be present: chestnut above the eyes, on both sides of the muzzle and inside on the edge of the ears. These markings may extend to other body regions as a transition between white and black. The head must always present black, blue or brown markings in the frontal region and the ears; there may be a white blaze and white marks preferably on the frontal groove and lateral parts of the muzzle, distributed as harmoniously as possible.
Height: At the withers: Males from 14 - 16 inches (34 - 40 cm), Females from 13 - 15 inches (33 - 38 cm)
Weight: maximum 22lbs (10kg)
Faults: Any departure from the forgoing points should be considered a fault and the seriousness with which the fault should be regarded should be in exact proportion to its degree.
Disqualifying Faults: Lack in structure, Not upright, Long or atypical hair, Faults in the typical characteristic markings, Full erect ears, Too heavy or too loose in the shoulders, viciousness or shyness, croup not slightly sloping, Overshot or undershot bite, Lack of harmony ,atypical build, Males: lack of two apparently normal testicles fully descended into the scrotum.