He is an active terrier of medium bone, strongly put together, suggesting endurance and agility, but rather narrow in shoulder, body and quarter. The body is covered with a somewhat broken though close-fitting and intensely wiry jacket. The characteristic "otter" head with its keen eye, combined with a body poise which is "at the alert," gives a look of fearless and implacable determination characteristic of the breed. Since the Border Terrier is a working terrier of a size to go to ground and able, within reason, to follow a horse, his conformation should be such that he be ideally built to do his job. No deviations from this ideal conformation should be permitted, which would impair his usefulness in running his quarry to earth and in bolting it therefrom. For this work he must be alert, active and agile, and capable of squeezing through narrow apertures and rapidly traversing any kind of terrain. His head, "like that of an otter," is distinctive, and his temperament ideally exemplifies that of a terrier.
Similar to that of an otter. Eyes dark hazel and full of fire and intelligence. Moderate in size, neither prominent nor small and beady. Ears small, V-shaped and of moderate thickness, dark preferred. Not set high on the head but somewhat on the side, and dropping forward close to the cheeks. They should not break above the level of the skull. Moderately broad and flat in skull with plenty of width between the eyes and between the ears. A slight, moderately broad curve at the stop rather than a pronounced indentation. Cheeks slightly full. Muzzle short and "well filled." A dark muzzle is characteristic and desirable. A few short whiskers are natural to the breed. Nose black, and of a good size. Teeth strong, with a scissors bite, large in proportion to size of dog.
Neck, Body, Topline
Neck clean, muscular and only long enough to give a well-balanced appearance. It should gradually widen into the shoulder. Back strong but laterally supple, with no suspicion of a dip behind the shoulder. Loin strong. Body deep, fairly narrow and of sufficient length to avoid any suggestions of lack of range and agility. The body should be capable of being spanned by a man's hands behind the shoulders. Brisket not excessively deep or narrow. Deep ribs carried well back and not oversprung in view of the desired depth and narrowness of the body. The underline fairly straight.
Shoulders well laid back and of good length, the blades converging to the withers gradually from a brisket not excessively deep or narrow. Forelegs straight and not too heavy in bone and placed slightly wider than in a Fox Terrier. Feet small and compact. Toes should point forward and be moderately arched with thick pads.
Muscular and racy, with thighs long and nicely molded. Stifles well bent and hocks well let down. Feet as in front.
A short and dense undercoat covered with a very wiry and somewhat broken topcoat which should lie closely, but it must not show any tendency to curl or wave. With such a coat a Border should be able to be exhibited almost in his natural state, nothing more in the way of trimming being needed than a tidying up of the head, neck and feet. Hide very thick and loose fitting.