Are Jack Russell Terriers Aggressive?

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Different dog breeds have different levels of aggression depending on what they were initially bred for. Before adopting a Jack Russell Terrier, it is important to know whether it is aggressive, especially if you have small children in your home. So, are Jack Russell Terriers aggressive?

Are Jack Russell Terriers Aggressive?

Jack Russell Terriers are naturally aggressive dogs, especially towards other pets and strangers or when provoked. They are also highly possessive and can get aggressive over their toys and food.

The territorial nature, especially in male Jack Russell Terriers, also contributes to their aggression when they see or hear an intruder in the environment. 

Close up view of a Jack Russell Terrier dog

However, you can reduce aggression in Jack Russell Terriers with proper discipline, training, exercise, and socialization. Some of the personality traits, environmental and lifestyle factors that cause aggression in Jack Russell Terriers include:


Since Jack Russell Terriers were initially bred for hunting foxes, they are naturally ready to guard their prey just like other hunting dogs. In the same way, hunting dogs protect their territory from other hunters, Jack Russell Terriers also try to protect their homes from intruders and strangers.

That means a Jack Russell Terrier is jealous and can’t tolerate seeing a new pet in its environment. Remember that the possessive nature can make Jack Russell Terriers aggressive against their family members if they play around with their food and toys.


Although Jack Russell Terriers are known to be brave dogs, they can fear if they hear a sudden loud noise like that of fireworks, especially if they are in a new environment. However, unlike other dog breeds, Jack Russell Terriers demonstrate their fear by being aggressive. 

Typically, it’s because the dog will be feeling threatened and become aggressive in a bid to protect itself. Since Jack Russell Terriers are loyal to their owners, they may also feel anxious and nervous and become aggressive if you don’t give them enough attention or when they detect you are about to leave them alone.

Excess Energy

Jack Russell Terriers are energetic dogs and need rigorous exercises such as daily jogging, hiking, or long walks to help expend excessive energy. Usually, they will take a nap after intense exercise. 

Picture of a JRT dog with a sky background

If you don’t engage them in intense exercises, they will resort to other methods of expending energy, such as aggressively growling, barking, and destructively scratching and biting toys. 

Health Conditions

Sometimes the dog might have injuries or underlying health conditions causing pain or discomfort. Since you might not notice it at first, you might go ahead to play with the dog or engage it in the usual physical exercises.

Since the dog doesn’t understand the root cause of the pain, it may think you are the cause and become aggressive. In most cases, you can tell whether the aggression results from injuries if the dog becomes aggressive all of a sudden when you touch certain spots of its body. 


Jack Russell Terriers have a strong pack mentality and act as the pack leader. If you don’t confidently act as the family leader, the dog will assume the leadership role. When this domination behavior develops, the dog becomes aggressive when you try to force it to do things. 

That means the dog will want to exercise excessive freedom and take any command as a provocation. For instance, the dog will take it as a provocation to take a toy away from it or force it down from furniture, making it aggressive. 

Tips to Reduce the Aggressiveness of a Jack Russell Terrier 

Jack Russell Terrier aggression can be risky, especially around small children. The following exercise, motivation, and training techniques can help you reduce the aggressiveness of a Jack Russell Terrier.

Jack Russell looking over the field
  • Solve the hyperactivity: If you suspect your dog is aggressive due to boredom, lack of exercise, and excess energy level, engage it in around 30 to 45 minutes of intense exercises such as jogging.
  • Reward non-aggressive behaviors: When the dog becomes aggressive, command it to calm down. If it does, reward it with treats and praises
  • Train the dog while still young: In most cases, adult Jack Russell Terriers are aggressive due to a lack of proper socialization with other pets and people while still young. Train your Jack Russell puppies to share the same place and food with other pets and to be comfortable around other people 
  • Consult a professional trainer: If the dog is excessively aggressive, you can contact a professional trainer to help train your dog. The trainer can also determine whether the aggression results from injuries or underlying health issues.

Related Questions 

How Can I Know That My Jack Russell Terrier Is Playing and Not Being Aggressive?

You can know a Jack Russell Terrier is playing if it’s rolling on its back while playing with the other dogs, toys, or pets. However, if the Jack Russell Terrier is constantly chasing the other pet in hot pursuit or body-slamming it, it is a sign of aggression.

Can Ignoring an Aggressive Jack Russell Terrier Help?

In most cases, ignoring an aggressive Jack Russell Terrier can help reduce aggressive behaviors. Usually, dogs see it as a reward when you react to unwanted behaviors such as aggression, especially if it’s seeking attention. 

Final Thoughts 

Jack Russell Terriers are generally aggressive dogs, especially towards strangers, pets, and family members who provoke them. Since aggression can be risky, especially around children, you can try to reduce it by training the dog, engaging it in intense exercises, and rewarding good behavior.