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Pain and Pet Behavior: Learn How They’re Linked

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In some ways, the fact that pain will affect how a living creature behaves is obvious. If I have a bad headache, I’ll stop writing this article and go lie down. If my dog steps on something sharp, she’ll stop walking and hold up her paw.

But even for an experienced pet owner, it can be easy to miss the connection, as happened recently when my Pug suddenly became reluctant to go for a walk. I spent an embarrassingly long couple of days trying to figure out why she had become afraid of the stairs in front of the house – till she actually started limping and I realized that the problem was that it hurt to walk down them.

Some connections between pain and behavior are even harder to catch – in fact, often a problem we categorize as “bad” behavior is a sign that something physical is wrong. And it’s so important to be aware of these potential connections, because our pets have no other way to tell us it hurts.

Aggression and Changes in Sociability

When a pet becomes snappy with other members of the household – whether other pets or humans – we call that a behavior problem, but it can be a sign of physical discomfort. Pets who suddenly start acting aggressively when touched should be evaluated for pain.

Pain can also affect interactions in more subtle ways. If a pet has become less playful and interactive, that can be a red flag, even if you don’t see obvious changes in their movement. Pain specialist Mike Petty, DVM, says to think about when you’ve had a sore arm: you can still use it because you know how to move it without hurting, but you may be reluctant to let someone shake your hand. The same could be going on with a dog who’s reluctant to play: “They’re afraid it’s going to hurt, and that decreases their sociability.”

These problems can develop so slowly over time that owners don’t realize it’s happening. “One of the first things I discovered when I stared doing pain management was that people would come in and say the dog is cranky–or not even mention it,” says Dr. Petty, “but once we got the pain under control, I’d often hear people say, ‘For the first time in ages my dog is playing with my other pets.’”

Looking for Change

When it comes to diagnosing pain, you and your veterinarian need to be a team. The clues are not always obvious in the exam room, says Petty. “We will see dogs limp across the parking lot and then quit limping when they hit the front door.”

But in many cases, it’s difficult to detect the problem in one exam because the clues come from changes over time. “Owners being aware of changes is what’s helpful for us. What’s the difference in the behavior now compared to six months ago?” says board-certified veterinary behaviorist Margaret E. Gruen of North Carolina State University.

Dr. Gruen is coauthor of a recent paper published in the journal Animals that reviewed the records of 100 dogs seen by 13 veterinarians. They found that conservatively, a third of them involved some form of pain, and in some cases possibly up to 80 percent.

Be attentive to behavior changes and share the information with your veterinarian, even if they don’t seem to have an obvious medical explanation. Changes in eating or drinking, sleeping or grooming habits, decreased stamina on walks, or changes in use of furniture or stairs can all be clues to an underlying medical issue, including undiagnosed pain.

Inappropriate Elimination

Another behavior issue that can be a result of pain is inappropriate elimination. Most cat owners are aware that if their cat goes outside the box, it can be a sign of urinary or bladder problems. But especially as cats age, a reluctance to use the box can be due to pain. “Oftentimes, it’s a problem with the litter box – the sides are too high, or the substrate is too painful to walk on,” says Petty.  The latter may be surprising, but think about it, he says: “If you have a sore ankle, which would you rather walk on, a firm surface, or deep sand?” He recommends trying special litters for senior cats that are easier for them to walk on.

A dog who “forgets” housetraining can also be suffering from pain, he says. If it hurts to walk, a dog may be reluctant to go find someone to ask to go out, or may dread going down the stairs to the outdoors. They may go to the door and urinate or defecate there, or simply start doing it wherever they are in the house. So not only should you never punish your dog for doing this, you should get a medical workup to see if there’s a physical problem.

Cognitive Issues

Because both pain and cognitive decline happen as pets age, it can be tricky to tell which is going on. “Severe chronic pain cases look a lot like cognitive dysfunction cases,” says Gruen. Some of the signs are the same, and even those that aren’t can be misinterpreted – for example, if a dog is standing on a rug and looking stuck there, it could be cognitive disorientation or the dog could be reluctant to walk across a slippery floor because it hurts to do so.

Likewise, decreased sociability is a common result of cognitive dysfunction, but it’s also possible that the dog isn’t following you around anymore because moving is uncomfortable, says Petty: “If the dog bed is in the family room and you’re in the kitchen, he’ll say ‘Nah, this is comfy; I’ll stay here.” Pain could also be why the dog doesn’t seem to want to play anymore.


While pain medication can make a big difference in your pet’s life, be aware that that may be only one part of the plan.

“We need to know what the medical conditions are, but that doesn’t necessarily mean that treating that alone will solve the behavior problem,” says Gruen.

For example, noise phobia in dogs often gets worse with age, and this may be due to pain. “A dog who is a little bit afraid of fireworks or thunder, as they get older and have some joint pain, they tense the muscles when they hear it, it gets that much more painful, and that gets associated with the noise,” she says.  So as well as treating underlying pain, behavior modification to break that association may be necessary. The same may be true for cats who associate the pain of a urinary tract infection or arthritis with their litter box.

Finally, it’s important to consider what changes you may need to make so pets can enjoy life despite physical problems. “If the dog loves the ball but he’s arthritic and painful and all you ever do is use a fling thing and throw it a hundred yards away, the dog’s going to look at you and say ‘Forget it,’” says Petty. So instead of assuming he doesn’t want to play anymore, try something new: “Maybe he wants you to roll the ball and walk it back. We may to have modify our own expectations of how we’re going to interact.”

This article was reviewed/edited by board-certified veterinary behaviorist Dr. Kenneth Martin and/or veterinary technician specialist in behavior Debbie Martin, LVT.

Linda Lombardi writes about the animals that share our planet and our homes for magazines including The Bark, websites including National Geographic and, and for the Associated Press. Her most recent book, co-authored with Deirdre Franklin, is The Pit Bull Life: A Dog Lover’s Companion.

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