When choosing a dog, it's important to choose the breed that's right for you. In order to do that, you need to know the characteristics and temperament of the breed you're thinking about adopting or purchasing before you do so.

Developed in England in the 19th century by a clergyman by the name of Rev. Jack Russell to hunt small game, particularly fox, by digging quarry (prey) out of its den, the Jack Russell terrier has good hunting and tracking ability and is considered a "working terrier."

Jack Russells are usually perky, happy, energetic, spirited, friendly, intelligent, loving, loyal, bold and assertive. They can make great companions but can become willful and need rules and limitations. They need a strong-willed owner who will be their "pack leader." They have strong hunting instincts and like to chase, bark and dig. If allowed to run loose in the country, Jack Russell terriers may chase small animals and dig down into their dens and stay underground with their "prey" for days, with no food or water.

This breed of dog enjoys games and playing with toys and is generally kind to children but will not tolerate abuse by them. They need plenty of exercise because of their high energy and tend to get restless and destructive if not occupied and well exercised. They are not usually lap dogs.

Jack Russell terriers are highly trainable, if shown authority, and able to perform impressive tricks but need an experienced trainer. They can be aggressive towards other dogs if they have been allowed to take over. Because of their strong hunting instincts, they can't be trusted with smaller animals. They can climb and jump. A Jack Russell that stands 12 inches tall can easily jump 5 feet. They are adaptable to most climates.

Some of the characteristics of a Jack Russell include being over 51% white (or all black) and can have black, brown or tan spots, found mainly around the face and at the base of the tail. The undercoat has a pattern of small brown and black spots that can't be seen on the outer coat. There are three different types of coats - smooth, rough and broken, and all coats shed. The ears fold downward, and the teeth are strong. The tail is held upright, high and straight and is usually docked shortly after birth to about 4 to 5 inches. Their full-grown height is usually 10 to 15 inches, and weight is 14 to 18 pounds.

Health problems that can occur in Jack Russell terriers are kneecap dislocation, inherited eye diseases, deafness, Legg-Perthes (a hip joint disease), epilepsy and skin conditions, but the life expectancy is about 15 years or more.

Grooming is fairly simple for Jack Russells. They should be combed or brushed regularly with a firm bristle brush, with bathing only when necessary.

Jack Russell terriers do okay in an apartment but are very active and need sufficient exercise or will become a nuisance. They do best with at least an average-sized yard with lots of space to run, hunt and play.

This breed of dog makes a great companion and is very loving, loyal and protective but needs a lot of attention and discipline, so it's best to determine if you have the time and energy for this breed before choosing it.