Size: The Jack Russell Terrier has a shoulder height of 33-35 cm (13-14 in) and weighs 6-8 kg (14-18 lbs). It has a flat skull, small eyes, small, V-shaped ears pointed toward the face, and powerful teeth which form a level or scissors bite (scissors preferable). The Jack Russell Terrier has a flat back, high, happy tail which is docked, and small, round ‘cat feet’. Forelegs should be straight and strong; crooked legs may be an indication of Achondroplasia. Working Terriers (‘Jack Russell Terriers’) should have chests less than 14 in at their widest. The Jack Russell Terrier is taller than it is long.
Coat: There are three different types of Jack Russell Terrier coat. The smooth-haired Jack Russell Terrier has thick, smooth hair, about a centimeter in length, over its entire body. The rough-haired Jack Russell Terrier has a double coat up to 10 cm in length over its entire body. The broken coated Jack Russell Terrier is a mix of the two. All coats are dense and coarse. Jack Russell Terriers are more than half white with tan, black, lemon, or tricolor markings. Markings are preferably restricted to the head and base of the tail.
Character: The Jack Russell Terrier is brave (sometimes excessively so), boisterous, observant, and self-confident. Owning a Jack Russell Terrier requires an ample supply of patience; they are great matches for exuberant owners who are prepared to entertain and exercise them, but are not for everyone.
Temperament: The Jack Russell Terrier gets along well with children, other dogs, and any household pets. It should be socialized when young if possible. It is however, still a hunting dog, so it sometimes can't resist the urge to chase the family cat. It may try to be dominant over other dogs, regardless of size. Visitors will always be announced with a distinctive bark. Jack Russell Terriers are fond of children, but they will become aggressive quickly if mishandled, so they should be monitored around small children.
Care: All three Jack Russell Terrier coat types are relatively low maintenance. Jack Russell Terriers should be brushed with a rubber brush when shedding to remove dead hairs. Occasionally, the coat of the rough-haired variety will need to be plucked. Jack Russell Terriers are known for their good health and long life span of 15 or even 20 years. Puppies should be tested for deafness.
Training: The Jack Russell Terrier learns quickly but will always try to have its own way. Consistency in training is key. It will try to win you over with its mischievous charm, but do not be fooled! Jack Russell Terriers are able to learn a variety of games and excel in events such as dog agility and Earthdog competitions.
Activity: The Jack Russell Terrier has a seemingly inexhaustible supply of energy. It must be given many opportunities to burn it off. Jack Russell Terriers need to run and play, and enjoy agility skills and playing catch. Digging, barking, and staging escapes are their way of telling you they need more exercise. Jack Russell Terriers are happiest on a farm or a home with a large backyard where they can frolic, and will not enjoy life in an apartment.