Cat Pain Detection Guide: How to Spot Discomfort Early

Cats are masters at hiding pain. In the wild, showing weakness could attract predators, so cats evolved to mask discomfort. For cat owners, this is a problem. By the time a cat obviously shows they’re unwell, things may already be serious. But there are tools now that can help you catch it earlier.

Why Do Cats Hide Pain?

Cats’ ancestors were solitary predators that were also prey for larger animals. In that environment, showing weakness meant exposing yourself as an easy target. Even though domestic cats now live safely, this instinct remains.

This means cats won’t howl or whine like dogs do when in pain. Mild to moderate pain often shows no obvious behavioral changes. By the time a cat is obviously hiding, not eating or drinking, the situation may already need urgent attention. That’s why the subtle signs matter.

The Feline Grimace Scale

In 2019, researchers at the University of Montreal published the Feline Grimace Scale (FGS), a tool for assessing pain in cats based on facial expression. It’s been validated in clinical studies, and you don’t need any training to use it.

Use the interactive tool below to assess your cat. Score each of the 5 facial features from 0-2 based on what you observe:

Pain Assessment Tool

Select a score for each feature based on your cat's current expression

1

Ear Position

View

0

Forward, upright

1

Slightly rotated outward

2

Flattened outward and back

2

Eye Squint

View

0

Eyes open

1

Partially squinted

2

Markedly squinted

3

Whisker Tension

View

0

Relaxed, hanging down

1

Slightly forward

2

Stiff and forward

4

Muzzle Shape

View

0

Relaxed and round

1

Slightly tense

2

Tense and oval

5

Head Position

View

0

Above shoulder line

1

Level with shoulders

2

Below shoulder line

0

Total Score (out of 10)

Likely no obvious pain

Continue monitoring your cat's behavior regularly.

Reset

How to Assess Correctly

When to Observe: Choose a time when your cat is resting quietly. Avoid assessing right after waking, eating, or during play.

Key Points: Look at the overall picture, not just single features. Know your cat’s normal “baseline” expression.

Common Mistakes: Don’t mistake sleepy eyes for pain squinting. Observe at multiple times before concluding.

Other Pain Signs

Besides facial expression, these behavioral changes may also indicate pain:

Activity changes: Fewer jumps, hesitation when jumping, altered gait or limping, lying down more than usual.

Routine changes: Decreased appetite, changes in grooming habits, altered bathroom behavior.

Behavior changes: Hiding more often, reduced interest in interaction, increased aggression when touched.

When to See a Vet

See a vet if:

• Feline Grimace Scale score is 4 or above
• Pain signs persist more than 24 hours
• Other symptoms appear like not eating, not drinking, vomiting, or diarrhea
• Your cat is limping or refusing to move
• Strong reaction when touching a specific area

Cats won’t tell you they’re hurting, so you have to look. The Feline Grimace Scale gives you a concrete way to do that instead of guessing. Score your cat when something seems off, and if the number hits 4 or above, don’t wait.

Frequently Asked Questions

How do I know if my cat is in pain? Watch for facial changes: squinted eyes, ears pulled apart and rotated outward, tense whiskers, a tense muzzle, and a lowered head. The Feline Grimace Scale scores these 0-2 each. A total of 4 or above suggests pain. Also watch for hiding, not eating, limping, or flinching when touched.

What is the Feline Grimace Scale? A pain assessment tool developed by researchers at the University of Montreal in 2019. It scores five facial features (ears, eyes, whiskers, muzzle, head position) on a 0-2 scale. It’s been scientifically validated and can be used by anyone, not just vets.

Can cats cry from pain? Cats don’t cry tears from pain the way humans do. Some cats may vocalize (yowl, hiss, or growl) when in acute pain, but many stay silent. That’s why facial and behavioral cues matter more than sound.

What FGS score means my cat needs a vet? A score of 4 out of 10 or higher. If you score your cat at 4+, schedule a vet visit. If the score is high and your cat is also not eating or showing other symptoms, go sooner.