How to Read Horse Facial Expressions for Pain and Stress

By Dr Duncan Houston

Horses do not always show pain in obvious ways.

Some will not scream, thrash, or collapse. They may simply stand quietly with a tight face, fixed ears, strained nostrils, tense jaw, or a look that owners often describe as “not quite right.” That subtlety is exactly why learning to read facial expression can be useful.

The important warning is this: a horse’s face is not a full diagnosis. Facial tension can be caused by pain, fear, stress, fatigue, environment, handling, or anticipation. But when facial tension appears with changes in appetite, movement, behaviour, manure, vital signs, or performance, it becomes a serious clue.

Quick Answer

Horse facial expressions can help owners detect possible pain or stress earlier, especially when using structured tools like the Horse Grimace Scale. The Horse Grimace Scale scores six facial features from 0 to 2, with higher scores suggesting more visible facial tension associated with pain. It should be used as an early warning tool, not as a replacement for a veterinary exam, because stress, fear, environment, and handling can also affect the face. The original Horse Grimace Scale study found it could be a potentially effective and reliable method for assessing pain after routine castration, but the authors also noted that more research was needed across different painful conditions. (PLOS)

What Is the Horse Grimace Scale?

The Horse Grimace Scale, or HGS, is a structured way to assess facial expressions that may indicate pain in horses.

It was developed in a study of horses undergoing routine castration. Researchers compared facial images before and after surgery and identified specific facial action units that became more obvious when horses were painful. In that study, horses undergoing castration had significantly higher Horse Grimace Scale scores 8 hours after the procedure compared with before surgery. (PLOS)

The scale uses six facial features:

Facial feature	What you are looking for
Stiffly backward ears	Ears held back in a fixed, tense way rather than casually moving
Orbital tightening	Tightness around the eye, giving a narrowed or strained look
Tension above the eye	Wrinkling, tightening, or a worried appearance above the eye
Strained chewing muscles	Tension or prominence in the masseter muscles along the jaw
Strained mouth and pronounced chin	Tight lips, pinched muzzle, or a tense chin
Strained nostrils and flattened profile	Nostrils that look tight, pulled, or abnormally shaped

Each feature is scored as 0 if absent, 1 if moderately present, and 2 if obviously present. The maximum total score is 12. (PLOS)

In plain English: the tenser the face, the more suspicious you should be that the horse may be uncomfortable.

Is the Horse Grimace Scale Measuring Pain or Stress?

Mostly pain.

This distinction matters because a lot of people casually use the word “stress” when what they really mean is discomfort, fear, anxiety, frustration, or pain.

The Horse Grimace Scale was developed as a pain assessment tool. Later research also suggested it may be useful in horses with acute laminitis at rest. (PubMed)

However, emotional state can influence parts of the face too. A pilot study looking at different emotional states found that HGS scores generally stayed low in non-painful situations, but fear tended to increase backward ear posture and chewing muscle tension. The authors concluded that HGS appeared promising as a pain tool, but negative emotional states can overlap with some facial signs. (ScienceDirect)

That is the clinical reality: facial expression is useful, but context is everything.

A horse with tense ears during a noisy feed time may be stressed or defensive.

A horse with tense ears, tight eyes, strained nostrils, reduced appetite, raised heart rate, and reluctance to move may be painful.

Same face. Very different level of concern.

Why Horses Hide Pain

Horses are prey animals. In the wild, obvious weakness can make an animal more vulnerable, so horses may suppress dramatic signs of pain until the problem is advanced. The original HGS paper specifically notes that pain assessment in horses is difficult because horses cannot verbally communicate and may mask obvious signs of pain in the presence of potential predators, including humans. (PLOS)

This is why subtle signs matter.

A horse that is “just quiet” may be coping.

A horse that is “just being difficult” may be painful.

A horse that “always pins his ears” may have a learned behaviour, poor handling history, chronic discomfort, or pain that has been normalised for too long.

In practice, the face is not the only thing I look at. I want to know what the horse is doing with the rest of the body: posture, weight shifting, appetite, manure, breathing, heart rate, movement, response to touch, and behaviour around people or other horses.

The Six Facial Signs to Watch

1. Stiffly Backward Ears

Ears move constantly in healthy horses. They listen, orient, communicate, and react.

The concern is not a brief ear flick. The concern is ears held stiffly backward, especially when the horse is otherwise quiet, withdrawn, or showing other discomfort signs.

Possible causes include:

• Pain

• Fear

• Irritation

• Defensive behaviour

• Resource guarding

• Saddle or girth discomfort

• Dental or bitting pain

• Ear pain

• Handling anxiety

Do not diagnose pain from ears alone. Ear position is useful, but horses are not radio antennas with one fixed meaning.

2. Tight Eyes

A painful or stressed horse may have a narrowed, tightened, or “hard” eye.

Look for:

• Tight eyelids

• Wrinkles above the eye

• A worried or strained look

• Less soft blinking

• A withdrawn stare

• Reduced interest in the environment

The equine pain face research describes facial changes involving the ears, eyes, nostrils, and muscle tension during induced pain. (PMC)

A tight eye becomes more concerning if the horse also has lameness, colic signs, fever, appetite change, eye discharge, squinting, or head shyness.

3. Tension Above the Eye

Tension above the eye may appear as wrinkling, raised tissue, or a pinched expression.

This can happen with pain, but also with fear, alertness, or environmental stress.

The decision point is simple: if the tension appears briefly during a stressful moment and then relaxes, it is less concerning. If it is persistent at rest, especially with other clinical signs, take it seriously.

4. Strained Chewing Muscles

The masseter muscles sit along the jaw and are involved in chewing. A horse may show visible tension or clenching in this area when uncomfortable.

This can be associated with:

• Dental pain

• Bit discomfort

• Jaw tension

• Stress

• Fear

• Abdominal pain

• Orthopaedic pain

• General discomfort

Newer adaptive horsemanship research in veterans with PTSD measured multiple horse welfare markers, including stress-related behaviours, hormones, and surface electromyography of the masseter and brachiocephalic muscles. In that study, horses involved in the adaptive horsemanship lessons showed fewer stress-related behaviours than control horses, and control horses had higher cortisol later in sessions. (ScienceDirect)

The practical takeaway is not that jaw tension diagnoses stress by itself. It is that horse welfare assessment is moving toward combining observable behaviour, physiology, and muscle activity instead of relying on guesswork.

5. Tight Mouth and Pronounced Chin

A horse in pain may show a pinched mouth, tight lips, or a more pronounced chin.

This can be subtle. Some horses look like they are holding tension through the whole lower face.

Common causes to consider include:

• Dental disease

• Bit or bridle discomfort

• Girth pain

• Back pain

• Colic

• Laminitis

• Hoof pain

• Post-procedure pain

• Anxiety during handling

A tight mouth during bridling is not automatically “bad manners.” It can be pain, anticipation, fear, confusion, or learned resistance.

6. Strained Nostrils and Flattened Facial Profile

The nostrils may look tight, flared, or pulled in a way that makes the side of the face appear flatter or more strained.

This becomes more concerning if paired with:

• Increased breathing effort

• Sweating

• Colic signs

• Painful stance

• Lameness

• Fever

• Depression

• Reduced appetite

If the nostrils are flared because the horse has just exercised, that is different from flared or strained nostrils in a horse standing quietly and looking unwell.

Normal Facial Expression vs Concerning Facial Tension

Situation	Usually less concerning	More concerning
Ears	Brief ear movement, listening, reacting	Fixed backward ears with dullness or pain signs
Eyes	Soft, blinking, alert	Tight, narrowed, worried, or withdrawn
Jaw	Relaxed chewing or resting face	Clenched or prominent jaw tension
Mouth	Soft lips and relaxed muzzle	Pinched mouth, tense chin, tight lips
Nostrils	Mild flare after exercise	Strained nostrils at rest with distress signs
Whole face	Changes with environment and then relaxes	Persistent tense expression at rest

The most important word is persistent.

A momentary expression is a clue. A repeated or sustained pattern is a signal.

Can Owners Use the Horse Grimace Scale at Home?

Yes, with caution.

The Horse Grimace Scale can be useful as an early warning system for owners, stable managers, and caretakers. The original HGS paper specifically suggested it could be implemented as an on-farm early warning tool when used alongside other behaviour-based methods. (PLOS)

A practical way to use it:

1. Take baseline photos of your horse when relaxed and healthy.

2. Take similar photos when you are concerned.

3. Compare the ears, eyes, jaw, mouth, chin, nostrils, and overall expression.

4. Score each feature from 0 to 2.

5. Record the total score.

6. Repeat over time to look for trends.

7. Combine the score with appetite, manure, movement, vital signs, and behaviour.

Do not obsess over one photo. A bad camera angle, bright sun, flies, feed anticipation, or another horse nearby can change the face.

A rising score, repeated tense expression, or tense face plus abnormal behaviour is far more useful than one dramatic snapshot.

What Score Should Worry You?

There is no perfect owner-friendly cutoff that diagnoses pain in every situation.

As a practical guide:

HGS pattern	What it may mean	What to do
0 to 2 and horse is normal	Usually low concern	Keep monitoring
3 to 5 or repeated mild tension	Possible discomfort, stress, or early pain	Check the full horse and monitor closely
Around 6 or higher, or rising scores	More concerning if persistent	Arrange veterinary advice, especially if other signs are present
High score plus abnormal appetite, movement, posture, manure, or vitals	Potentially serious pain	Contact your vet promptly

The score should never override the horse in front of you.

A horse with a low score can still be sick.

A horse with a high score may be fearful rather than painful.

But a horse with a tense face, reduced appetite, abnormal posture, raised heart rate, or reluctance to move deserves attention.

Risk Framework: How Worried Should You Be?

Low Risk

Low risk means the facial tension is brief, linked to an obvious mild trigger, and resolves quickly.

Examples include:

• Ears back briefly when another horse approaches feed

• Tight expression during a loud noise, then relaxation

• Temporary alertness in a new environment

• Mild tension during grooming that disappears when the trigger is removed

Action: Monitor and record. Look for patterns, but this is not usually an emergency if the horse is bright, eating, drinking, moving normally, and passing manure.

Moderate Risk

Moderate concern means facial tension is recurring, situation-specific, or affecting behaviour.

Examples include:

• Tense face every time the saddle is placed

• Tight mouth during bridling

• Jaw tension during ridden work

• Ears back during grooming or girthing

• Repeated tense expression after farrier work

• Mild performance change with facial tension

Action: Investigate. Check saddle fit, dental health, hooves, back, workload, training, and handling. Arrange a vet, dental, farrier, or saddle-fit review depending on the pattern.

High Risk

High concern means facial tension is persistent at rest or appears with other signs of illness or pain.

Examples include:

• Tight face while standing quietly

• Reduced appetite

• Reduced manure

• Mild colic signs

• Lameness

• Reluctance to move

• Fever

• Abnormal gum colour

• Sweating without exercise

• Depression or isolation from the herd

Action: Contact your veterinarian promptly. Same-day advice is often appropriate.

Critical Risk

Critical concern means facial tension is paired with signs of severe pain, systemic illness, or emergency disease.

Examples include:

• Repeated rolling

• Severe colic signs

• Non-weight-bearing lameness

• Suspected laminitis

• Difficulty breathing

• Collapse

• Neurological signs

• Eye injury or severe squinting

• Choke

• Severe trauma

• Profound depression

• Rapid deterioration over hours

Action: Treat this as an emergency.

What Else Could Facial Tension Mean?

Facial tension is a clue, not a diagnosis.

Important causes to consider include:

Pain-related causes

• Laminitis

• Hoof abscess

• Colic

• Dental disease

• Eye pain

• Back pain

• Neck pain

• Saddle fit pain

• Tendon or ligament injury

• Arthritis

• Wounds

• Post-surgical pain

• Gastric ulcers

• Reproductive pain

• Muscle soreness

Stress or fear-related causes

• Trailering

• New environment

• Isolation from companions

• Harsh handling

• Loud noise

• Competition atmosphere

• Clipping

• Veterinary or farrier procedures

• Unfamiliar equipment

• Social conflict

• Feed competition

• Confinement

Management-related causes

• Poor saddle fit

• Inappropriate bit

• Overtraining

• Lack of turnout

• Unstable herd dynamics

• Poor sleep

• Heat stress

• Insect irritation

• Inconsistent routine

The common mistake is deciding the horse is “naughty” before asking whether the horse is uncomfortable.

In practice, pain must be ruled out before behaviour is blamed.

When Is This an Emergency?

Facial tension becomes urgent when it appears with red flag signs.

Call a vet urgently if your horse has:

• Colic signs such as pawing, flank watching, rolling, sweating, stretching, loss of appetite, depression, or fewer bowel movements

• Severe lameness

• Reluctance to move

• Strong digital pulses

• Heat in the hooves

• Rocked-back stance

• Laboured breathing

• Abnormal gum colour

• High heart rate at rest

• Severe depression

• Collapse

• Neurological signs

• Eye injury or a painful closed eye

• Choke signs

• Deep wounds or heavy bleeding

• Sudden deterioration over a few hours

Merck Veterinary Manual lists common colic signs including repeated pawing, looking at the flank, kicking at the abdomen, lying down, rolling, sweating, stretching as if to urinate, loss of appetite, depression, and reduced bowel movements. (Merck Veterinary Manual)

Merck also describes severe lameness with bounding digital pulses as a hallmark clinical sign of laminitis, with severe cases potentially involving rotation or sinking of the coffin bone. (Merck Veterinary Manual)

A tense face with normal appetite and normal movement is one thing.

A tense face with colic signs, laminitis signs, or severe depression is not a watch-and-wait situation.

What Should You Do Next?

If your horse looks tense but otherwise normal

Observe quietly from a distance for 5 to 10 minutes.

Check:

• Is the horse eating?

• Is the horse drinking?

• Is manure normal?

• Is the horse moving normally?

• Is the horse interacting normally?

• Is the horse breathing normally?

• Does the face relax when the trigger is removed?

If everything else is normal and the expression resolves, record it and keep monitoring.

If the expression keeps coming back

Look for a pattern.

Ask:

• Does it happen during saddling?

• During bridling?

• During grooming?

• During farrier work?

• During ridden work?

• At feeding time?

• When separated from another horse?

• After exercise?

• On hard ground?

• In the stable but not paddock?

Patterns are clinically useful. “He looks tense sometimes” is vague. “He tightens his mouth and ears every time the girth is fastened” is useful.

If your horse looks tense and unwell

Check basic health markers if safe:

• Temperature

• Heart rate

• Respiratory rate

• Gum colour

• Capillary refill time

• Gut sounds

• Digital pulses

• Appetite

• Manure output

• Lameness or reluctance to move

Then contact your vet if anything is abnormal.

If your horse is painful or deteriorating

Do not wait.

Do not keep riding.

Do not force the horse through the behaviour.

Do not give medication unless your vet advises it, especially in suspected colic, because pain relief can mask important clinical signs.

Call your vet with photos, videos, timing, vital signs, and what changed.

How to Take Useful Photos or Videos

Good images make facial assessment much easier.

Try to capture:

• The horse at rest

• A side view of the head

• A front view if safe

• Both eyes if possible

• The muzzle and nostrils

• The ears

• A short video before and after the suspected trigger

• The full body posture, not just the face

Avoid:

• Flash directly in the face

• Photos while the horse is eating

• Photos during bright glare

• Angles that hide one side of the face

• Only taking images during dramatic moments

The best comparison is always your horse against your horse.

Baseline photos when healthy are extremely useful. Without a baseline, it is easier to overinterpret a normal expression or miss a real change.

Common Mistakes Owners Make

Assuming ears back always means bad behaviour

Pinned or backward ears can mean irritation, fear, pain, resource guarding, or learned defence. It is not automatically bad manners.

Using the Horse Grimace Scale as a diagnosis

The HGS helps identify possible pain. It does not tell you the cause.

Ignoring the rest of the horse

The face matters, but so do appetite, manure, movement, posture, breathing, heart rate, gum colour, and behaviour.

Punishing resistance before ruling out pain

A horse that resists saddling, bridling, picking up feet, or moving forward may be trying to communicate discomfort.

Comparing one horse to another

Some horses naturally have different facial shapes and expressions. Compare your horse to their own normal baseline.

Relying on one photo

One image can mislead you. Trends and repeat observations are more useful.

Waiting too long because the horse is “still standing”

Standing quietly does not mean comfortable. Stoic horses can be very painful.

How to Reduce Pain and Stress Signals in Horses

You cannot prevent every painful condition, but you can reduce many avoidable causes of facial tension.

Practical prevention includes:

• Routine dental checks

• Regular farrier care

• Saddle and bridle fit reviews

• Careful workload progression

• Adequate warm-up and recovery

• Prompt investigation of lameness

• Pain control after veterinary procedures

• Calm handling

• Consistent routine

• Safe turnout

• Social contact with compatible horses

• Reduced feed competition

• Good parasite control

• Monitoring appetite, manure, weight, and behaviour

• Recording facial expression changes over time

For performance horses, pay close attention to facial tension during tacking up, mounting, early work, transitions, jumping, collection, and after exercise.

For older horses, facial tension may be linked to arthritis, dental disease, chronic hoof pain, PPID, reduced vision, or difficulty lying down and rising.

For young horses, tension may reflect confusion, fear, pain, poor handling, dental eruption, or equipment pressure.

For therapy, riding school, and lesson horses, repeated mild facial tension can be easy to normalise because the horse is “used to it.” That is exactly why structured observation matters.

What About Therapy Horses and Human Stress?

Well-managed equine-assisted programs can be positive, but horse welfare still needs monitoring.

A 2024 study of ground-based adaptive horsemanship lessons for veterans with PTSD found that horses involved in the lessons showed fewer stress-related behaviours than control horses, and the authors reported that adaptive horsemanship lessons elicited less stress than control conditions. (ScienceDirect)

Rutgers’ summary of the same research reported that the participating horses did not display indicators of stress compared with horses separated from the sessions. (Rutgers University)

That is encouraging, but it does not mean every program is automatically safe for every horse.

Good therapy and lesson programs should still monitor:

• Facial expression

• Body tension

• Avoidance behaviour

• Ear and eye changes

• Stress behaviours

• Workload

• Rest days

• Handler consistency

• Suitability of each horse

• Health and soundness

A kind program is not just good for humans. It must be good for the horse too.

FAQs

Can horses really show pain in their face?

Yes. Research has identified facial changes associated with pain in horses, including changes around the ears, eyes, nostrils, muzzle, and facial muscles. The Horse Grimace Scale was developed to score these changes in a structured way. (PLOS)

Is the Horse Grimace Scale for pain or stress?

It is mainly a pain assessment tool. Stress, fear, and other emotional states can affect some facial features, so the score must be interpreted with context, behaviour, movement, appetite, vital signs, and the situation.

What does it mean if my horse pins their ears?

Pinned ears can mean many things, including pain, fear, irritation, food guarding, social conflict, or learned defensive behaviour. If it happens repeatedly during saddling, grooming, handling, or ridden work, investigate discomfort before assuming the horse is being difficult.

Should I call a vet for a tense facial expression?

Call a vet if the tense expression is persistent, worsening, or appears with lameness, colic signs, reduced appetite, abnormal manure, fever, abnormal breathing, abnormal gum colour, or depression. If the horse is otherwise normal and the expression resolves quickly, monitor and record the pattern.

Can I use photos to track my horse’s pain?

Yes. Photos and videos can be useful, especially when compared with baseline images of your horse when healthy and relaxed. Take consistent side and front views, and include body posture and behaviour where possible.

Final Thoughts

A horse’s face can tell you a lot, but only if you read it properly.

The Horse Grimace Scale gives owners and vets a more structured way to notice facial tension linked to pain. That is valuable. But the face should never be interpreted in isolation.

The real question is not just “does my horse look tense?”

The better question is: “Does this facial expression fit with pain, stress, fear, illness, or a change in normal behaviour?”

If the horse relaxes quickly and everything else is normal, monitor.

If the expression keeps returning, look for the trigger.

If the expression appears with appetite changes, lameness, colic signs, abnormal vital signs, or depression, call your vet.

Your horse may not be able to tell you what hurts, but the face can be one of the first places the body whispers before it starts shouting.

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If you are unsure whether your horse’s facial expression is normal, stress-related, pain-related, or part of a bigger health problem, ASK A VET™ can help you decide what can be monitored, what needs a routine check, and what should be treated as urgent.