It’s hard to know when pets are in pain because they can’t communicate the same way people do. But different species of animals do show pain in their own ways. For example, when predators like dogs are in pain, they often cry or whimper and act differently than prey animals like rabbits or horses. Prey animals often hide their pain, which makes it even harder to notice.
Veterinarians use vital signs, behavior changes, pain scales, and the animal’s history to assess pain.
Vital signs (such as heart rate, breathing rate, and blood pressure) can be used to assess pain, especially during surgery or after serious injury. However, measurements of vital signs can’t show where pain is coming from, such as from surgery or from something else. Pets with chronic pain may have normal vital signs. These signs can also change because of stress, fear, or other medical issues (like anemia), not just pain. Even if a pet's vital signs look normal, it could still be in pain.
Behavioral changes are often hard to notice unless you know what is normal for that animal. Some pets hide pain well. For example, a dog might still wag its tail and greet people in spite of being in pain. Pain behaviors of animals can be very different from those of people. A cat sitting quietly at the back of its cage after surgery might be in pain, but a caregiver could miss it if they’re looking for more obvious signs, like pacing, agitation, or meowing.
Chronic pain signs are usually harder to notice than sudden pain from injury or surgery. Signs like decreased activity or appetite, weight loss, or poor grooming don’t always mean pain but do show something is wrong. Describing how your pet acts around family is very important in helping the vet evaluate chronic pain. And if your pet becomes more active after getting pain medicine, that can show the pain was causing the behavior changes.
Pets with cancer might show signs of both acute and chronic pain, so watch for changes carefully.
Pain scales are tools vets use to rate how much pain an animal has. They includes questions about the animal’s species, breed, age, environment, cause of pain, body area affected, and how long and intense the pain is. Scales that consider behaviors specific to dogs or cats are most accurate for assessing pain in these species. Even with a good pain score, it can be hard to know how well a pet is coping with pain.
