SORTING OUT WHAT SNORTING MEANS

New research from France suggests that snorting is a sign of contentment in horses.

Researchers at University of Rennes-Caen Normandie observed 48 horses kept in four different environments. Half of the horses lived at commercial riding schools. They were used for riding lessons, fed twice a day and turned out four to six hours daily. The remaining horses were kept on continual turnout, fed free-choice hay and ridden for pleasure occasionally. These two environments, the researchers say, represent opposite points on a spectrum extending from highly restricted living to a natural lifestyle.

The researchers observed each of the horses in fiveminute intervals at various times throughout the day, both when they were alone and when they were near other horses. The riding school horses were each observed in their stalls as well as during turnout.

During the observation periods, the researchers documented the types of noises/ vocalizations the horses made, what they were doing at the time they made them and their apparent emotional states. They also assigned each horse a total chronic stress score (TCSS) based on the number of aggressive reactions, stereotypic behaviors, time spent with ears back while eating and the percent of time spent facing the wall when in a stall.

At the outset of the study, the researchers distinguished snorts from similarsounding respiratory events: “The ‘snore’ is a very short raspy inhalation sound produced in a low alert context, such [as] investigating a novel object or obstacle .... The ‘blow’ corresponds to a short very intense nonpulsed exhalation through the nostrils and is generally

associated with vigilance/ alarm postures) … the ‘snort’ corresponds to a more or less pulsed sound produced by nostril vibrations while expulsing the air, with a slightly longer duration in comparison to the blow.”

The data revealed that snorts were usually associated with positive situations, such as feeding, and with positive internal states, such as the horse having his ears forward. The horses who lived on pasture snorted twice as much as did the riding school horses. In addition, the latter group snorted more often when turned out than when confined to their stalls. The frequency of snorts was negatively correlated with TCSS; horses with a high stress score produced fewer snorts.

The researchers note that the results rule out snorting as purely a hygienic function to clear the nostrils, particularly since horses snorted less often in the dustier, indoor environments. Instead, they conclude, “snorts appear [to be] a possible reliable indicator of positive emotions which could help identify situations appreciated by horses.” Reference: “An unexpected acoustic indicator of positive emotions in horses,” PLOS One, July 2018