Bred for hunting foxes, the Jack Russell Terrier is an energetic and aggressive breed. It requires a lot of exercise and often exhibits behaviors such as digging, chasing small animals, and picking fights with larger dogs.
Fiercely loyal and possessive, this breed makes a great hunting animal or pet for a single person household but can be difficult to own as a family pet without diligent obedience training.
The Jack Russell Terrier gets its name from Reverend John Russell, who originally bred them for hunting foxes. Dogs used in fox hunting at the time were sometimes mistaken for the animals they were hunting, so Russell purchased a white and tan terrier female in 1819 and started a breed of primarily white dogs that would not be mistaken for foxes.
The needs of fox hunting, specifically the need for stamina and courage to chase a fox through the forest and into its hole, dictate many of the Jack Russell Terrier’s characteristics. These include their energetic and often aggressive nature, the urge to dig, their fearlessness, and their intelligence.
Fox hunting also dictates not only their coloring but their build. Their small size, clean shoulders and straight legs make them ideal for chasing small animals.
The coat of a Jack Russell Terrier is primarily white, but it often contains black and tan markings. Its coat can be short or long, respectively termed smooth or rough, or it can be a mixture of the two known as a broken coat. The broken coat can be a number of combinations of short and long hair, but is usually longer around the face and tail.
Jack Russell Terriers stand 30 to 36 cm (12-14 inches) tall and weight roughly 5-8 kg (13 to 17 pounds). They are a compact, well-balanced breed, giving them an edge when hunting their quarry.
The Jack Russel Terriers tend to believe they are much larger than they actually are, leading to aggressive behavior including an eagerness to fight much larger dogs.
As previously noted, Jack Russell Terriers are fearless, intelligent, and very vocal. Because they were bred for hunting, they often exhibit behaviors that many people mistakenly classify as bad habits such as digging, barking, following scents, and chasing small animals. In addition, they need just as much exercise as a larger dog. For these reasons, they need a yard with a secure, tall fence that they cannot dig beneath.
They are often very possessive of their owner or their favorite member of the family and often require a basic level of professional obedience training to avoid destructive aggression toward others. Jack Russell Terriers will not tolerate mistreatment and are usually not a good mix with small children. They are often a danger to cats and other dogs due to their aggressive nature.
While Jack Russell Terriers generally have a long lifespan of 13-16 years and remain healthy throughout most of their lives, they fall prey to several serious ailments.
These can include hereditary eye disorders such as ectopia lentis and cataracts as well as musculoskeletal issues such as patellar luxation, a disease in which the kneecap slips away from its normal position and can cause ligament injury as well as arthritis. Regular checkups and careful attention to the terrier’s behavior should warn you of any impending issues.