Factors such as medical conditions, anxiety, stress, hormonal changes, and disrupted sleep can affect a horse's mood swings. | Photo: Erica Larson/The Horse

Q: My gelding, whom I bred and raised, has always seemed moody, especially compared to my other horses. I swear he came out of the womb with his ears pinned! One day he’s happy and ready to work or eager for attention, the next he’s sour and grinding his teeth. Some days he’s anxious, and some days he’s calm. There’s no rhyme or reason to it. I know some people feel mares are moody, as well. Is there any research about horse moods and how they influence training?

—Nicole, via e-mail

A: 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