Jack Russell terriers originated in England. The breed was ideal for hunting due to the dogs' small size, sturdy bodies and inquisitive demeanor. Named for the parson who bred them, the Reverend John Russell, they're quick, agile and intelligent -- ideal hunting pals. Recognized by the American Kennel Club as Russell terriers, they are not the same as Parson Russell terriers, their long-legged cousins.
Jack Russells are cheerful, spirited dogs. They are full of energy and playfulness, and can be great companions for active individuals. They love to walk, run and frolic, and are in their happiest element when they have plenty of exercise and playtime with their pack leader.
Jack Russells are known to be highly intelligent dogs and as a result are easy to train. They can learn tricks quickly and can maintain that memory to perform tricks for a long time. They have been used in television and movies because they are easy to train and teach.
Terriers are hunting dogs, and this breed maintains a sharp hunting instinct. This breed is an expert at digging and jumping. If not properly controlled, the Jack Russell will chase other small animals. The Jack Russell therefore needs plenty of exercise and lots of behavior training from an experienced owner to reduce this natural urge of the breed. Two of these will wear one another out in many cases, but pairing the Russell with a dog who doesn't have the same high energy is asking for trouble.
Unless the Jack Russell terrier is trained to understand he is not the pack leader, he will exhibit small dog syndrome, whereby he believes he is the pack leader to all humans. This can result in excessive barking, snapping, possessive or guarding behavior, and willfulness. A well-trained Jack Russell will not exhibit these negative behaviors, but a Jack Russell must be trained early in life, and the training must be vigorously reinforced for a lifetime.