Pain or Stress Can Be at the Root of Dog Aggression

A very common dog bite scenario is when a person needs to handle a dog that is in pain. Most people are pretty forgiving about a bite that happens this way. They find it understandable that a dog in pain might lash out if touched or approached. It is generally accepted that the dog reacted instinctively without actually wanting to hurt anyone. What people are less forgiving of is the dog that develops aggression due to stress. People generally don’t even recognize stress as the underlying cause of their dog’s aggression. Perhaps if we think of stress as “emotional pain” we could find more forgiveness and understanding while diagnosing and treating the dog’s aggression. Ok, let’s take a quick look at how pain and stress are related to dog aggression. 

Physical Pain or Discomfort: Pain, chronic or acute, mild or severe, can put a dog in a defensive or protective state which can trigger aggression.  

  • Injury, arthritis, illness – there are endless possibilities for chronic or acute causes of physical pain or discomfort.   
  • Getting bumped into can trigger an aggressive reaction.  
  • Being touched, even gently, can trigger an aggressive reaction.
  • Extra sensitive or protective of personal space due to concerns of being bumped or touched. 
  • General grumpiness due to not feeling well.
  • Dogs often don’t show obvious signs of their pain. 
    • How would you know if a dog has a headache? 
    • How would you know if a dog was hangry?
    • Sometimes a visit to the vet is in order to check for pain, injury or illness.  

Stress: There’s an old adage that goes something like, “Hurt people, hurt people.” We understand that this refers to people who have been emotionally hurt, right? Well, when dogs are under stress, they are mentally or emotionally “hurting” and that’s why I am lumping it into the same category as physical pain. Dogs have the same, or at least very similar, emotions that we do, therefore, like us, they can experience emotional pain.

  • Stress is a form of mental discomfort or “emotional pain” 
  • Fear is a form of stress or emotional pain. (see: Fear
  • Being stressed can make dogs grumpy and edgy…much like humans. 
    • Some dogs get stressed (grumpy) when they are tired as well. Hence the old adage, “Let sleeping dogs lie.” 
  • Accumulated Stressors: The accumulation of multiple stressors, many of which have already been covered throughout this series, can cause a buildup of internal pressure until the dog finally explodes. Chronic underlying levels of stress keep the dog on edge almost constantly, which is really unhealthy and sets the stage for overreaction or hypersensitivity to triggers. Here are just a few examples of accumulating stressors: 
    • Health Problems – discomfort, physical pain (see above) 
    • Fear and anxiety – (see: Fear and Hyperactivity)
    • Tight leash – causes frustration which is a form of stress. (see: Tight Leash
    • Lack of Proper Exercise – lack of fulfillment, boredom and pent up energy. (see Frustration and Hyperactivity
    • Lack of Proper Socialization – lack of “social practice” makes social situations very stressful for some dogs. (see: Frustration, Fear)
    • Lack of Clarity – conflict or confusion regarding basic rules of life, basic communication systems or basic obedience commands is frustration inducing. What are the rules? What are you saying to me? How am I supposed to behave? 
    • Lack of Leadership – conflict or confusion about who’s in charge. If the dog is allowed, or forced, to assume the dominant role there will most likely be a large amount of stress put on the dog. Being the pack leader is a stressful job. (see: Dominance)  
    • Lack of Freedom – excessive confinement via leashes, crates, fences and walls.  (see: Frustration)


Physical pain as well as stress (mental/emotional pain) should be considered as potential underlying factors when analyzing dog aggression cases. Looking at things holistically (looking for the why before treating the what) can be a total game changer, not only when working with aggression cases but with pretty much any dog behavior problem I can think of. If you are interested in a deeper understanding of canine aggression, please read the entire series. Links are provided below. There is also a four part series on Dog Psychology that ties in nicely with this one. Read them all and become a dog training super genius!

Chad Culp – Certified Dog Trainer, Canine Behavior Consultant, Owner of Thriving Canine. 

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