If you don’t like horses, this article is not for you.

If you do, you’ll be intrigued to learn that scientists have collected evidence in favor of a theory that many frequent riders or horse owners have long presumed: A snorting horse is a happy horse.

Writing in the journal PLOS ONE, lead author Mathilde Stomp and her colleagues from the Université de Rennes, France, explain how their comprehensive observations of 48 horses refute the possibility that snorts are simply a means of nostril-clearing and indicate instead that they are a consistent auditory signal that the animal is in a cheerful mood.

“These results provide a potential important tool as snorts appear as a possible reliable indicator of positive emotions, which could help identify situations appreciated by horses," Stomp said in a statement.

According to the researchers, investigations into the behavioral and physiological cues associated with animal happiness are often limited or inconclusive because the experimental conditions are not the sort of situations where any creature would be comfortable (would you enjoy being pushed into a pen by an overly enthusiastic stranger who doesn’t speak your language?), or they are very different than the creature’s natural environment or living situation. Furthermore, they note, very few studies have ever attempted to assess the emotional association of acoustic yet non-vocal signals.

Hoping to fill this gap in knowledge and confirm the suspected meaning of snorts, Stomp’s team performed behavioral sampling on 25 geldings, 18 females, and five stallions, representing a total of 18 breeds. The horses were housed at four sites: two riding schools and two leisure horse stables. One author observed each horse’s ear position – a well-known indicator of equine distress or relaxation – and the number of snorts during five-minute intervals while in the stall and out in the pasture. 

Overall, the team logged 560 snorts, finding no difference in frequency between horses of differing ages or sex. There were, however, telling differences in the setting and context of the snorts. Study horses snorted two times more frequently when in the pasture vs the stall and significantly more often while eating compared with other activities. In addition, more snorts were documented when the horse’s ears were facing forward or sideways and no snorts were noted when the animal was displaying aggression to another horse or human.

“Air conditions/dust cannot explain the present results as different horses in the same air conditions [differed] in terms of snort production,” the authors concluded. “… Snort production was also associated with more positive posture and preferred activities such as foraging, or in a quiet observation, two activities reflecting relaxed quiet states.”

This adds to our knowledge of these complex creatures, that can also read human body language and communicate using their own facial expressions.