Skip to content

get free shipping on any order

get free shipping on any order

10% off any subscription order

10% off any subscription order

Page Overlay

need our help choosing the right supplement for your fur-baby?


Are Jack Russell Terriers Aggressive? A Guide for Owners

Are Jack Russell terriers aggressive? Some health conditions and bad training practices can encourage aggression. Here’s how to prevent poor behavior.

Are Jack Russell Terriers aggressive: Jack Russell Terrier sitting on a mat

Are Jack Russell terriers aggressive? Some health conditions and bad training practices can encourage aggression. Here’s how to prevent poor behavior.

Any dog lover looking for a new furry friend wants a well-adjusted and even-tempered companion. When you’re deciding on a purebred dog, like the Jack Russell terrier (or JRT), you might wonder about the JRT’s reputation. Are Jack Russell terriers aggressive?

To be clear, any dog can become aggressive if they don’t receive early socialization and attentive handling. A large study, reported on by the New York Times, found that only 9% of a dog’s behavior is linked to their breed — making the breed of dog a poor predictor of aggressive behavior

However, dog breed can help us predict genetically inherited health problems that can lead to aggression. And choosing a purebred puppy allows you to assess the personalities of its parents.

We’ll explain the risk factors that can lead to Jack Russell aggression, and we’ll take a look at steps dog owners can take to prevent aggressive behavior in JRTs and other breeds — including tips for choosing a Jack Russell puppy with a low risk of aggression.

Are Jack Russell Terriers Aggressive?

Are Jack Russell Terriers aggressive: Jack Russell Terrier biting a ball

While we can’t predict every individual dog’s personality based on breed, we can look at the breed‘s genetically inherited health conditions and the job it was bred to do. 

But, in the case of Jack Russell dogs, we’re actually talking about two breeds.

The American Kennel Club (AKC) split this breed into two in the early 2000s with larger JRTs being classified as Parson Russell terriers and smaller JRTs being classified as Russell terriers. However, because the two types of JRTs share such a similar genetic lineage, they also share similar histories and health problems

Here‘s how these factors could affect aggression in both types of Jack Russell dogs.

  • Health problems: JRTs are considered a healthy breed. They don’t typically inherit health conditions that can lead to aggression (including rage syndrome, cognitive dysfunction, or brain tumors). However, these dogs sometimes develop joint issues that can be painful, and pain can cause a dog to act irritably or aggressively. If your typically well-behaved dog suddenly shows signs of aggression, contact your vet to rule out a health problem.
  • Hunting dog history: JRTs were bred to chase foxes and rodents. Because of this history, the breed has a high prey drive and can be aggressive toward small animals and cats. Always supervise your JRT around small animals.

Small Dogs and Aggression

Are Jack Russell Terriers aggressive: Jack Russell Terrier playing with a Golden Retriever

Jack Russell Terriers are small dogs, and in the case of aggression, size matters. According to an American Veterinary Medical Association (AVMA) literature review that looked at dog bite data, veterinarians and owners reported much higher levels of aggressive behavior from small and medium dogs than they did from large dogs.

The AVMA‘s review states that this is likely due to smaller aggressive dogs receiving less training. A small dog, like an aggressive Pomeranian or Chihuahua, doesn't cause as much damage as a large dog, like an aggressive German shepherd or pit bull, so owners feel less pressure to prevent their small dog’s poor behavior.

This conclusion is supported by a survey of over a thousand dog owners, conducted by the University of Veterinary Medicine in Vienna and reported by the AKC. The survey found that small dogs were less likely to receive consistent training and had more behavioral problems because of it. Training and socialization are two of the most important ways dog owners can prevent aggressive behavior.

How Can Dog Owners Prevent Aggressive Behavior?

Woman playing with a Jack Russell Terrier

The National Canine Research Council found that dog owners’ mismanagement of dogs was one of the biggest factors in aggression. As a Jack Russell terrier owner, you can do a lot to prevent aggressive behavior and keep your dog, yourself, and your other family members safe. And you can start taking steps to prevent aggression before you even bring your new dog home. 

Here’s what to do:

Work With a Responsible Breeder

A responsible breeder is dedicated to improving the health and temperament of their breed. They run AKC-recommended health screenings, and they raise their dogs in their homes as beloved pets. They should always be willing to let you visit their homes to meet their dogs. Some breeders will also provide early socialization by introducing the puppies to children, taking them on car rides, or raising them with cats.

Meet Your Jack Russell Puppy’s Parents

A responsible breeder will let you visit their home and meet their dogs, so make sure you do. At a minimum, you should be able to meet the puppy’s mother. (Sometimes the father is a stud dog with a different owner.) Make sure the parents have a nice energy level and a friendly disposition.

Find a Reliable Rescue Dog

If you’d rather rescue an adult Jack Russell terrier instead of a puppy, work with a rescue organization that tests their temperament. The rescue should be able to tell you if the dog is reactive to children, strangers, or other dogs. If you rescue an adult Jack Russell terrier that already has behavioral problems, you can work with a professional trainer or animal behaviorist to rehabilitate the dog, but you should expect it to be a time-intensive (yet extremely rewarding) task. 

Start Socialization at an Early Age

Lack of socialization can lead to fear of new people or new situations, which can lead to aggression. From the minute you bring your Jack Russell puppy home, start taking them to cafes, parks, and other dog-friendly locales. Introduce them to as many different types of people as possible, including people of different ages, sizes, races, and abilities. Make each new situation positive by providing lots of treats.

Use Positive Reinforcement Training 

This dog training technique relies on treats and praise to reward good behavior. The majority of professional trainers consider it more effective than dominance training, which relies on yelling and punishment and can encourage more aggression in some dogs (that will match your aggression with their own).

Provide Plenty of Exercise 

Lack of exercise can lead to a variety of behavioral problems, as your dog may choose to use their excess energy to destroy your furniture or terrorize the family cat. Jack Russell terriers have high energy levels and need plenty of exercise, but because of their small size, they’re often easy to exercise with a game of fetch in the park or yard.

Offer Lots of Mental Stimulation

JRTs are also highly intelligent dogs that like to work. If you don‘t direct that intelligence toward a positive task, like playing with chew toys or solving puzzle games, they may decide their job is to guard the couch or keep neighbors away from your windows with excessive barking. Try giving your Jack Russell a long-lasting natural Yak Chew to keep them occupied.

Learn to Recognize the Signs of Aggression

Even a typically well-behaved dog may become aggressive if they‘re scared. As their owner, you can prevent them from feeling this way by recognizing early body language cues that signal fear. 

If your dog is crouching, tucking their tail, raising their hackles, pinning their ears, or snarling, remove them from the stressful situation. Bring them to a quiet, familiar place and offer a calming chew.

Keep JRTs On-Leash Around Small Animals 

Jack Russell terriers have a high prey drive and may chase cats or small animals. To keep your dog from being aggressive toward smaller animals, keep them on leash. If you’re introducing your Jack Russell puppy to the family cat, keep them on the leash whenever the cat is around until they learn not to chase. Many JRTs can live peacefully with the family cat when they’re raised together from an early age, but they will likely continue to chase unfamiliar cats.

Raise a Small Dog With a Big Heart

Jack Russell Terrier lying his head on a person's hand

Jack Russell terriers are no more prone to aggression than any other dog breed. But their hunting dog history can lead these terriers to terrorize small pets and chase all the squirrels, rabbits, and mice in your neighborhood. Keep your JRT on its leash to keep small creatures safe.

Also, make sure to provide plenty of early socialization and training. Small dogs often get less consistent training from their owners than large dogs, which has led to more reports of aggressive behavior from small breeds. You can help improve small dogs‘ reputation by raising a well-adjusted Jack Russell terrier.

For more information on all your favorite dog breeds, visit the Native Pet blog.

illustration of dog's tail & the dog is digging

need our help choosing the right supplement for your fur-baby?

illustration of dog's tail & the dog is digging