Recognizing Pain in Cats and Dogs: A Guide for Pet Owners

Pain is one of the most important factors in assessing your pet’s quality of life, yet it’s often the hardest to recognize. Research shows that untrained pet owners frequently underestimate their pet’s pain levels, sometimes significantly. This isn’t because we don’t care—it’s because pain in animals can be subtle, and our pets can’t tell us where or how much it hurts.

Understanding how to recognize pain in your pet is essential, whether you’re managing a chronic condition, recovering from surgery, or navigating end-of-life decisions. Early recognition allows for pain management that can significantly improve your pet’s comfort and quality of life. In some cases, effective pain control can extend the quality time you have together.

The challenge is this: unlike humans who can describe their pain, our pets rely entirely on us to notice the signs they’re suffering. Those signs are often more subtle than we expect.

Animals can’t verbally communicate their pain, which means, as veterinary researchers describe it, pain in pets is “what the observer says it is” rather than what the patient reports. This creates a fundamental challenge.

Pain has two components: the sensory aspect (how it feels—the type, source, and intensity) and the emotional aspect (how it makes them feel). Without verbal communication, we have to rely on behavioral changes to recognize both.

The problem is that behavioral changes are often gradual. When you see your pet every day, it’s easy to miss subtle shifts in how they move, interact, or position themselves. Additionally, many pets maintain some normal behaviors even when in significant pain. A dog might still wag its tail and greet family members while limping on the stairs. A cat might still eat breakfast while suffering from severe dental disease.

Even in veterinary settings, pain can be difficult to assess because anxiety and fear during clinic visits can mask pain behaviors or be mistaken for them. This is why your observations from home—where your pet is relaxed and behaving naturally—are so valuable.

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If recognizing pain in dogs is difficult, recognizing it in cats can be even more challenging. Cats are biologically programmed to hide pain as a survival mechanism. In the wild, showing weakness makes an animal vulnerable to predators. Even though your cat is safe in your home, these evolutionary instincts persist.

This creates a significant problem: by the time a cat’s pain is obvious, the underlying disease or condition is often quite advanced. Research shows that cats are often undertreated for pain compared to dogs, partly because veterinarians report difficulty assessing feline pain and partly because the signs are so easily missed.

Understanding that cats actively hide their pain is the first step. The second is knowing what subtle signs to look for.

While every dog is unique, there are common behavioral and physical changes that can indicate pain. You know your dog best—what’s “normal” for one dog may be a warning sign in another.

Dogs in pain may show reluctance to walk, play, climb stairs, or jump onto furniture. They might withdraw from family interactions or avoid being touched in certain areas. Some dogs become more vocal—whining, whimpering, or growling when moved—though many remain quiet even when hurting. Restlessness is common: an inability to get comfortable, frequent position changes, or pacing. Changes in sleep patterns can occur, either sleeping much more than usual or having difficulty settling. Appetite often decreases, with less interest in food or treats. Perhaps most concerning, some dogs develop uncharacteristic aggression or irritability, snapping or growling when approached, especially if they’re normally friendly.

Dogs in pain often adopt altered postures—a hunched back, head held low, stiff movements, or obvious guarding of a specific body part. Limping or lameness is a clear sign, whether constant or intermittent. Excessive panting when the dog isn’t hot or hasn’t been exercising can indicate discomfort. Trembling or shaking, particularly when at rest, may signal pain. Finally, excessive licking or biting of one area of the body often means that spot is painful.

Keep in mind that changes are typically gradual, and dogs may show only one or two signs rather than multiple obvious indicators. Any persistent change in your dog’s behavior or physical presentation warrants veterinary evaluation.

Recognizing pain in cats requires paying close attention to both subtle facial expressions and behavioral changes.

In recent years, veterinary researchers at the Université de Montréal developed a remarkable tool called the Feline Grimace Scale. This validated assessment system is fast, reliable, and—importantly—can be used by both veterinarians and cat owners at home.

The breakthrough insight behind the Feline Grimace Scale is this: when cats are in pain, subtle changes occur in their facial expressions. Rather than relying on obvious signs like vocalization or dramatic behavior changes, the scale focuses on tension and positioning in specific areas of the cat’s face.

Researchers analyzed hundreds of cats before and after receiving pain relief and identified measurable facial changes that indicate pain. Each feature is scored on a simple scale, and the scores are added together to determine whether intervention is needed. Even cats who appear quiet and calm may show signs of pain through their facial expressions—you just have to know what to look for.

The Feline Grimace Scale is available for free online, complete with comprehensive training materials, scoring guides, and even a smartphone app that walks you through the assessment process step by step. We strongly encourage cat owners to visit the official Feline Grimace Scale website to learn how to use this valuable tool.

Important limitations to understand: The Feline Grimace Scale is validated specifically for acute pain—situations like post-surgical pain, injuries, trauma, or conditions like pancreatitis. It’s not reliable for assessing chronic pain conditions like arthritis.

Beyond facial expressions, cats in pain often show these behavioral changes:

Decreased grooming is common, leading to a poor coat condition or developing mats. Changes in litter box habits—avoiding the box entirely or eliminating outside of it—can indicate pain, particularly with conditions affecting joints or the urinary tract. Appetite changes, whether eating significantly less or stopping altogether, are important warning signs. Increased hiding or seeking isolation more than usual suggests a cat is not feeling well. Decreased activity shows up as less jumping, playing, or exploring than is typical for that individual cat. Changes in sleep location, such as avoiding favorite high perches and seeking ground-level spots instead, may indicate painful joints. Vocalization changes—becoming either more vocal than usual or unusually quiet—can signal discomfort. Finally, an altered response to touch, such as reacting negatively to being petted or picked up in areas they normally enjoy, often means those areas are painful.

Many owners attribute these changes to “just getting old,” but they frequently indicate pain from treatable conditions like arthritis, dental disease, or other medical issues that deserve veterinary attention.

The distinction between acute and chronic pain matters because they present differently and require different approaches to assessment. The primary difference is duration.

Acute pain develops suddenly and typically lasts from a few hours to several days or weeks. Examples include post-surgical pain, injuries, infections, or inflammatory conditions. Acute pain is often more obvious in presentation—you might see limping, vocalization, or guarding of a specific area. Tools like the Feline Grimace Scale and Glasgow Composite Measure Pain Scale work well for assessing acute pain.

Chronic pain persists for weeks to months, often lasting well beyond the typical healing time you’d expect. Examples include ongoing pain from osteoarthritis, cancer, dental disease, and chronic conditions like kidney disease. The challenge with chronic pain is that it’s much more subtle. Changes develop gradually over time, and owners may not notice the slow decline or may attribute it to normal aging. Chronic pain is severely underrecognized and undertreated, especially in cats.

An important note: Chronic conditions can cause acute pain episodes. For example, a pet with chronic arthritis might experience an acute flare-up of pain. The condition is chronic, but the pain episode is acute. This is why understanding both types of pain presentation matters.

For families considering end-of-life decisions, understanding chronic pain is particularly important. Many conditions that bring families to this difficult decision involve ongoing pain that has persisted over time. Recognizing what chronic pain looks like is essential for accurately assessing quality of life.

If you notice any of the signs described above, here’s what to do:

First, document what you’re seeing. Take videos of behavior changes—limping, difficulty rising, frequent position changes, or altered movement patterns. For cats, take photos that show facial expressions or unusual postures. Write detailed notes: When does the behavior occur? What makes it better or worse? How long has this been happening? When did you first notice it?

One helpful tool for tracking these observations is Hospet (www.hospet.app), a free app available for both iOS and Android. Hospet provides a structured system for documenting medical events, changes in behavior, and quality-of-life observations over time. It also makes it easy to share this information with your veterinarian, ensuring nothing important gets forgotten during your appointment.

This documentation is critically important. Anxiety and fear in the veterinary clinic can mask pain behaviors that are obvious at home. The videos and observations you share provide information your veterinarian can’t see during an exam but needs to make accurate assessments.

Second, contact your veterinarian. Don’t wait for symptoms to worsen. Even subtle changes warrant evaluation. Share your documentation—videos are especially helpful—and be specific about what you’ve observed and when it started.

Third, never attempt to self-medicate your pet. Many human pain medications are toxic to animals. Over-the-counter pet medications used without veterinary guidance can be dangerous. Even if you have leftover pain medications from a previous condition, don’t give them without consulting your veterinarian—the source and type of pain matters for appropriate treatment.

You’re not overreacting by reaching out. Any persistent change in your pet’s behavior is a valid reason to contact your veterinarian.

Recognizing pain is the first step toward managing it, and effective pain management can significantly improve your pet’s quality of life. Modern veterinary medicine has made tremendous advances in pain control. Many options exist, both pharmacologic medications and non-pharmacologic approaches, and multimodal pain management—using multiple strategies together—is often most effective.

For families facing end-of-life decisions, understanding your pet’s pain level is fundamental to quality-of-life assessment. However, the presence of pain alone shouldn’t automatically drive the decision toward euthanasia. The real question isn’t “Is my pet in pain?” but rather “Can we keep my pet comfortable?”

Manageable pain with effective treatment is very different from pain that’s difficult or impossible to control. When pain becomes unmanageable despite appropriate treatment, or when the side effects of pain control significantly compromise quality of life, that’s often when families find themselves in the euthanasia window.

Modern pain management can accomplish a great deal, but it can’t fix everything. Part of advocating for your pet is recognizing when pain has become a dominant factor affecting their daily experience and when comfort can no longer be reliably maintained.

Your pet relies on you to recognize when they’re hurting. By learning these signs, documenting your observations carefully, and trusting what you’re seeing, you’re giving your pet the gift of comfort and advocating for their wellbeing in the most fundamental way.

You know your pet better than anyone else. Trust your instincts. If something seems off, it probably is. Don’t hesitate to reach out to your veterinarian with your concerns. Recognizing pain is a skill, and you’re now better equipped to use it on behalf of the companion who depends on you. If you have any concerns about what you are seeing, or if you’d find a quality of life consultation helpful, we do offer that as a service option. To learn more about our quality of life consultations, click here.

This article draws on research and guidelines from:

• 2022 AAHA/AAFP Pain Management Guidelines for Dogs and Cats
• Cornell University College of Veterinary Medicine, Richard P. Riney Canine Health Center
• Evangelista MC, Watanabe R, Leung VSY, et al. Facial expressions of pain in cats: the development and validation of a Feline Grimace Scale. Scientific Reports. 2019;9:19128.
• Monteiro BP, Lee NH, Steagall PV. Can cat caregivers reliably assess acute pain in cats using the Feline Grimace Scale? A large bilingual global survey. Journal of Feline Medicine and Surgery. 2023;25(1).
• Pang DSJ. Feline Grimace Scale research, University of Calgary Faculty of Veterinary Medicine
• Journal of the American Veterinary Medical Association research on owner pain recognition

For more information on the Feline Grimace Scale, including free training materials and mobile app, visit: www.felinegrimacescale.com