Most of the time, Zelda is a perfect model of the noble steed. Her coat is gleaming, her expression is bright, her ears are pricked forward.
But Zelda also has a goofy side. Usually after a ride, or when I’m giving her a massage or a laser treatment, she makes the silliest faces. You have to love horses’ complete lack of self consciousness.
Why do horses yawn? There are many suppositions, but not necessarily a lot of answers. Some people, including vets, believe it’s a symptom of pain, including an indication of ulcers or even colic. Some people attribute yawning as a way a horse It’s not related to fatigue, but rather demonstrates a release of tension or the transition from a more stressful state to one of relaxation. Horses often yawn during body work, when they are processing or releasing the tension in their bodies, or after a stretch (almost all my horses have yawned when the farrier puts a hoof on their stand).
Back in 2016, a team of researchers in Europe set out to learn more about yawning in both domestic and Przewalski horses by observing them living in semi-natural conditions.
Aleksandra Górecka-Bruzda and her colleagues, writing in The Science of Nature, noted that horses provided the chance to compare not only animals living in different conditions, but also wild versus domestic species. Read the full study here.
Yawning is rare in herbivores which therefore may be an interesting group to disentangle the potential function(s) of yawning behaviour. Horses provide the opportunity to compare not only animals living in different conditions but also wild versus domestic species. Here, we tested three hypotheses by observing both domestic and Przewalski horses living in semi-natural conditions:
(i) that domestic horses may show an elevated rate of yawning as a result of the domestication process (or as a result of life conditions),
(ii) that individuals experiencing a higher level of social stress would yawn more than individuals with lower social stress and
(iii) that males would yawn more often than females.
The study involved 19 Przewalski horses (PHs) and 16 domestic horses (DHs) of different breeds living in large outdoor enclosures. The results showed that there was no difference between the PH and DH in yawning frequency (YF). PHs exhibited much higher levels of social interactions than DHs. There was a positive correlation between yawning frequency and aggressive behaviours in PHs, especially males, supporting the idea that yawning may be associated with more excitatory/stressful social situations. A correlation was found between yawning frequency and affiliative behaviours in DHs, which supports the potential relationship between yawning and social context. Finally, the entire males, but not castrated males, showed much higher levels of yawning than females in both species. The intensity (rather than the valence) of the interaction may be important in triggering yawning, which could therefore be a displacement activity that helps reduce tension.
Probably the most important thing is to keep track of when your horse yawns, so that you have a better understanding of what prompts their behavior. With Zelda, I’m pretty sure she yawns after exercise and releasing tension — either from stretching, riding or massage. With her, it often accompanies licking and chewing behavior. I tend to interpret it as a good thing.
What about your horse? Do they yawn at a particular time?