Moody Horses

Emotions have a powerful influence on how an individual behaves and views the world.1  The negative emotions that go along with mood swings can lead to pessimistic thinking and impact quality of life. Exactly what causes moodiness isn’t well understood. Various aspects of a horse’s environment and biology affect its emotional state, and a few of these are presented below.

If you are a horse owner or has been involved with horses at all you have heard the old saying “mood mares” are the worst! Let’s explore why that is….by the way all the mares that I have owned (2) were very sweet and not moody at all!

What Causes Mood Swings?DSCN2662_0011

Medical conditions

A veterinarian should exam a horses that experience mood fluctuations or persistent negative emotions. Moodiness can be a sign of underlying health issues that flare up periodically, such as allergies, joint and muscular pain, gastrointestinal issues, and disorders of the nervous and endocrine system. In humans, mood fluctuations are also associated with psychiatric conditions such as depression, bipolar disorder, and attention-deficit hyperactivity disorder. Whether horses suffer from these same mental disorders is not known. Previous injuries can cause occasional discomfort and associated changes in mood. If your horse grinds his teeth, it could be a sign that he is experiencing physical discomfort or stress.

Anxiety and stress

Moodiness has been linked to anxiety, and a string of bad days can lead to a loss of emotional control. Animals with an anxious temperament or who experience chronic stress tend to be more on edge, and negative emotions can be easily triggered by seemingly irrelevant or minor events. Interestingly, a recent study found that young horses showed larger swings in emotions than older horses in response in response to novel objects.2 Controlling mood swings caused by anxiety requires identifying and eliminating the sources of stress from the environment.

Hormonal changes

Hormones are known to play a role in controlling emotions and managing stress. They’re often blamed when a mare is moody, but much more is known about how hormones act on equine reproductive behavior than about how they affect emotions. Hormonal irregularities, including abnormal levels of thyroid and adrenal hormones, can cause fluctuations in emotions.  In humans, disruptions in daily activity can also lead to hormonal imbalances and increase the risk of mood disorders, including depression, bipolar disorder, and seasonal affective disorder.  It’s possible that disturbed routines also cause hormonal imbalances and moodiness in some horses. Sticking to a predictable routine by structuring activities at the same time every day can help maintain normal daily hormonal balance and stabilize mood.

“Keeping a journal can help identify patterns related to the horse’s shifting moods.”

Disrupted sleep

Disrupted sleep is closely linked to mood and anxiety disorders in humans, and when deprived of rapid eye movement (REM) sleep, people often become sad and irritable. Horses also suffer from sleep deprivation if they get less than 60 minutes of REM sleep a day, on average, for about a week. This can happen if the horse is unable to lay down in a laterally recumbent position, because of physical discomfort, insufficient space, insecurity about the environment, or social pressure.3 A horse deprived of REM sleep will become visibly drowsy, but it isn’t known if sleep disturbances are linked to negative moods in horses as they are in people.


Even when mood swings seem occur without rhyme or reason, the horse is probably reacting to something that the owner simply didn’t experience or notice. Events in the environment are nearly always involved to some extent in triggering negative emotions in a moody horse. Keeping a journal can help identify patterns related to the horse’s shifting moods.  It’s important to think broadly by looking at the horse’s routine, activities, locations, time of day, weather, social interactions, diet, and more.  Nutrition is considered a vital component to mood management; consult with an equine nutritionist for advice about your horse’s diet and feeding schedule.

Training the Moody Horsehorse-carrot

Figuring out the reasons for a horse’s mood swings can be complex, and negative emotions can interfere with and frustrate training. When your horse is having a bad day, being flexible and adopting a different approach can help. Below are some general strategies that can be used to protect against the emotional highs and lows.

  • Environmental and behavioral enrichment can reduce a horse’s baseline anxiety and vulnerability to stressors. Providing more positive experiences in general and during training can reduce a horse’s pessimistic outlook and improve mood.
  • Moody horses should get regular physical exercise, so don’t give up and put your horse back into his stall when he’s in a bad mood. Exercise causes the body to produce endorphins, and these hormones can help reduce the effects of stress and improve mood. Voluntary exercise is thought to be more beneficial than forced exercise.
  • Avoid punishing a moody horse; it will only make his negative outlook and emotions even worse. Instead, readjust your expectations and demands.  Set the horse up for success by removing stressors from the environment, asking the horse to complete simple tasks, and generously rewarding his small successes.

These strategies will have limited success if there is an underlying medical problem, so consult with a veterinarian first if your horse has emotional swings or persistent negative moods.



1 Briefer Freymond, S., Briefer, E.F., Zollinger, A., Gindrat-von Allmen, Y., Wyss, C., and Bachmann, I.  (2014) Behaviour or horses in a judgment bias test associated with positive or negative reinforcement.  Applied Animal Behaviour Science 158, 34-45.

2  Baragli, P., Vitale, V., Banti, L., and Sighieri, C. (2014) Effect of aging on behavioural and physiological responses to a stressful stimulus in horses (Equus caballus).  Behaviour 151, 1513-1533.

3 Larson, E.  (2012) Understanding equine sleep deprivation.  The Horse (April 4),

By Robin Foster, PhD, CAAB, IAABC-Certified Horse Behavior Consultant and comments by Diane Weinmann

Robin Foster, PhD, CAAB, IAABC-Certified Horse Behavior Consultant, is a research professor at the University of Puget Sound in Seattle, Washington, and an affiliate professor at the University of Washington. She holds a doctorate in animal behavior and has taught courses in animal learning and behavior for more than 20 years. Her research looks at temperament, stress, and burn-out as they relate to the selection, retention, and welfare of therapy horses. She also provides private behavior consultations and training services


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s