Happy yet prone to Mischief
Although Jack Russell Terriers are a "happy" breed, they are NOT as they are portrayed in the movies, on TV, or other forms of media. Those dogs are professionally trained and handled, and are very obedient only for VERY short periods of time. Celebrity dogs have their needs met by the trainer, and perform their jobs accordingly.
Dirt, Dirt and more Dirt
Jack Russell Terriers are bred to go underground, following scent to locate and bark at quarry until they are dug down to or the quarry bolts. If they do not have an outlet for their natural instincts, they will invent new and fun jobs for themselves, which frequently include guardian of the world and/or their possessions and family, chasing cars, hunting birds, bugs or leaves, or endlessly digging in the soil. While adaptable to a variety of environments, they are first and foremost bred to be hunting dogs. These little dogs require what may seem to be an extraordinary amount of human attention, outdoor activity, exercise, discipline and an understanding and acceptance of their hunting nature.
Bathing and Shedding
After getting dirty, Jack Russell Terriers are not overly fond of taking a bath (use a gentle shampoo). You do not want to bathe them too often as it can lead to dry skin. Please note that the Jack Russell Terriers is NOT a non-shedding breed! Smooth coats shed the most, dropping hair continuously year round. Rough coats maintain the guard and dead coat, requiring manual shedding a few times a year.
A Jack Russell Terriers should always be crate-trained. They can be very destructive if left unattended! Most behavioral problems are due to a lack of companionship, discipline, activity and exercise. If you've only seen perfect, well-behaved JR's, they are ones that were lucky enough to be exercised, well socialized, and trained.
Love to Dig
Jack Russell Terriers love to dig. You might want to say goodbye to your flower bed. They can also dig under, climb or jump over fences; some can climb trees and any height chain link fencing. The traits and skills that make them excellent hunting dogs (i.e., digging, barking, aggressive nature) are often interpreted as bad habits that cause people to give them up.
Aggressive Toward Other Dogs
Jack Russell Terriers are often aggressive with other dogs. Same-sex aggression and aggression towards other breeds of dogs is well documented with this terrier. It is strongly recommended that no more than two Jack Russells (of opposite sex only) ever be permitted to stay together unattended. There have been many instances of terriers being hurt, even killed, by their fellow terriers; even young pups over the age of eight weeks must be carefully monitored. It is imperative that prospective Jack Russell owners understand this part of the terrier's nature.
Big Dog ... Little Body
Jack Russell Terriers are a big dog in a little body. They have the same need (or more!) for exercise as a much larger dog... and the mentality to match -- they think they are at least 150 pounds, and are fearless, often challenging other dogs three times their size. It is said that the courage of the Jack Russell is never in doubt; surely a true statement. They require firm, consistent, responsible handing; they are very intelligent, determined and bold (sometimes to the point of abandon, which could be fatal).
About those Small Animals ...
Jack Russell Terriers are commonly known to harass, injure or kill other small pets, such as cats, birds, rabbits, mice, rats, etc., simply due to their strong natural hunting instinct. Raising a puppy with a cat does not guarantee the cat's life-long safety!
Jack Russell Terriers will not tolerate even unintended mistreatment from a child. They will not put up with typical child handling such as pulling of ears, tails, etc., or taking or "sharing" of the dog's bones, food, toys, etc. Jack Russells are not recommended for households with children under the age of six unless you are previously experienced with JRTs.
Jack Russell Terriers make wonderful parents. However, breeding is risky business and should not be undertaken lightly. Breeders should follow the Breeders Code of Ethics, have their breeding stock BAER and CERF tested, and breed only to JRTCA-registered terriers.
Loved by their Owners
Jack Russell Terriers can become very possessive of their owner or a favorite member of the family or of what they consider to be their personal property if allowed to do so to the point of showing aggressive protective behavior that must be controlled from an early age. However, their funny antics will continually amuse you, their intelligence seems to know no bounds and their assertive nature and boundless energy can at times be overwhelming.
On the Run
Jack Russell Terriers absolutely need a securely fenced yard! Jack Russells will roam due to their hunting instincts.... even if left in an unsecured for a few minutes! You can let them out every day for three years with no trouble.... but one day they will disappear and may never come back. Many JR's have been killed by cars by darting into the road in pursuit of a squirrel, cat, etc.
Jack Russell Terriers are fearless and require firm, consistent discipline. They are extremely intelligent, continue to test their limits throughout their life. More often than not, train their owners before the owner knows what has happened! This ability to train their owners can include displays of aggressive behavior. Their assertive nature must be understood and handled properly!
Jack Russell Terriers require a long-term commitment to obedience, activity, exercise and entertainment... their unique character, intelligence and high energy level can frustrate you, will undoubtedly entertain you, and can bring you great joy or great grief. If this type of relationship does not appeal to you, then consider another breed.