Jack Russell Terrier
The Jack Russell Terrier is a working breed with origins in fox hunting. It was bred in the late 1700s specifically to chase, but not kill, fox. Its small size is important to its purpose.
The Jack Russell Terrier generally weighs 14 pounds and has an average chest size of 12 to 14 inches. Its small size is useful in pursuing fox in small, underground dens. The breed can have one of three coat types: smooth, broken, and rough. The coat is always dense and soft and is predominantly white with black, tan or tricolor markings on the tail base and face. The undercoat and skin are often spotted or freckled. The ears of the breed fold downward. The tail is traditionally docked, and the legs are often slightly crooked. Its length and height are squarely proportionate.
The breed is an independent working dog. It is a very vocal breed, due to its origins, so that its master could hear it bark when it was underground. For this reason also, it may tend to dig holes. The breed has a strong personality and needs a firm-handed owner. A Jack Russell which is not well trained or regularly attended to and exercised may become unmanageable. It needs plenty of attention and exercise to maintain its well-being. The breed can get along with children and other animals, but it does not tolerate abuse and is quite fearless.
The Jack Russell Terrier is a fairly healthy breed which can live from 11 to 18 years of age. Health concerns with the breed include: hereditary cataracts, primary lens luxation, congenital deafness, medial patellar luxation, cerebellar ataxia, Legg-Calve-Perthes Disease, myasthenia gravis, atopy, general joint problems, and von Willebrand’s disease.