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9 Behavioral Signs Your Dog Is in Pain

Animal behaviorist Karen B. London breaks down the silent ways your pet is trying to tell you they’re hurting.

by Karen B. London, PhD
Updated January 15, 2022
Sad boxer rests on owners lap, dog doesn't want to be touched
Lucas Ottone / Stocksy

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For the first couple of weeks, our dog Bugsy enjoyed playing with our foster puppy. Then he changed, tiring of her quickly and often avoiding her, even growling if she approached him while he was on his bed. He stopped playing in the snow with her and would go to his bed rather than lie next to her on the rug. We figured that when she left, he would stop being sulky and return to his usual upbeat, playful self.

When Bugsy remained grumpy after her departure, we suspected that something was wrong. And it was. The veterinarian determined that he had a partial tear in his anterior cruciate ligament, or ACL (a knee ligament), and was probably in considerable pain. The way Bugsy was acting should have told me that he was hurting, because although most dogs are not obvious about it, there are many behavioral signs of pain. If you find that your dog is suddenly avoiding you or other things they previously enjoyed, it’s time to investigate.

Signs of Pain in Dogs

1. Changes in Behavior

Any change can mean something is wrong. If your dog is less energetic or less cheerful than usual, doesn’t engage in the activities they usually enjoy, acts restless, becomes unusually clingy, or stops socializing as much or as happily as they used to, they may be experiencing discomfort.

2. Nighttime Grouchiness

Even minor injuries or maladies can be exacerbated by the day’s activities, resulting in a cranky pup in the evening, when things slow down.

3. Good Days and Bad Days

If your dog acts like their normal self some days but is grumpy, aggressive, or otherwise different on other days, pain may be the cause.

4. Unusual Behavior After Strenuous Activity

Dogs who exhibit unexpected behavior after they have had more exercise than usual may be in pain. An injury or any kind of soreness may become worse with additional exercise, so if your dog is predictably out of sorts on such days, pain may be the culprit.

5. Suddenly Behaving Aggressively

If a fully mature dog suddenly exhibits aggressive behavior, it may be because they’re in pain. I’m especially alert to the sudden onset of aggression in a dog over the age of four, because dogs that age (or older) with no history of aggression rarely behave this way unless something is wrong.

Ask a Vet

6. Unwilling to Play

If a dog who usually takes any opportunity to play with reckless abandon ceases to be interested in playtime, it could be a sign that something hurts.

7. Avoiding Other Dogs

Sometimes when dogs are in pain, they don’t want other dogs near them, especially if those dogs are young, bouncy, or exuberant. If it is inconsistent with a dog’s personality to shy away from other dogs, doing so might mean they’re protecting an already tender area.

8. Loss of Appetite

A dog’s refusal to eat, which can have many causes, will almost always result in a trip to the veterinarian. Though sometimes the diagnosis is serious — liver failure or cancer, for example — not eating can also be a sign of pain from other less-alarming conditions.

9. Reacting Badly to Being Touched

If your dog reacts negatively to a touch that they would normally like (or ignore), that reaction may be due to pain. Typical negative reactions include yelping, leaping, whining, licking your hand, pulling away, or even growling. A pain-based reaction will usually only be displayed when a specific spot is touched.

If you have any reason to suspect that your dog may be in pain, make an appointment to see your vet right away, as we did with Bugsy. It was a relief to know exactly what was going on with him, and to be able to ease his misery. Only a veterinarian can diagnose a medical condition, but with astute observations of the behavioral warning signs, you can help save your dog from unnecessary suffering by seeking speedy medical help.

To identify an abnormality with your dog, you must first be able to recognize what is normal for them. You know your pup better than anyone else and you will have to decide when a situation requires veterinarian assistance. Changes in a dog’s behavior or body may be subtle, making noticing a problem more difficult. Learn the basics for doing an at-home physical exam of your dog.

Karen London holding up a small dog

Karen B. London, PhD

Karen B. London, Ph.D., is a Certified Applied Animal Behaviorist and Certified Professional Dog Trainer who specializes in working with dogs with serious behavioral issues, including aggression, and has also trained other animals including cats, birds, snakes, and insects. She writes the animal column for the Arizona Daily Sun and is an Adjunct Professor in the Department of Biological Sciences at Northern Arizona University. She is the author of six books about training and behavior, including her most recent, Treat Everyone Like a Dog: How a Dog Trainer’s World View Can Improve Your Life.