Did you know that, according to a number of studies, herbivores rarely yawn? This might come as a surprise to most horse owners; we frequently catch our charges yawning. Researchers believe the unusual frequency with which horses yawn could be a result of frustration with a less-than-natural domestic lifestyle.

Recently, a group of Polish and French researchers compared yawning patterns between horses living in a more natural environment and horses kept in restricted conditions.

The team used data from a behavioral study on 19 Przewalski’s horses living in semi-natural conditions and performed their own study with two groups of domestic horses living in similar conditions. Specifically, they sought to:

• Compare yawning frequency in Przewalski’s horses and domestic horses;
• Explore the possible connection between yawning and social interactions; and
• Compare yawning frequency between males and females.

“The (domestic) horses were kept outdoors year-round, eating plants typical of the local habitat and drinking water from natural sources (such as lakes and ponds),” said researcher Aleksandra Górecka-Bruzda, PhD, DSc, of the Institute of Genetics and Animal Breeding Department of Animal Behavior in Poland. “All studied horses were allowed to form social groups and social hierarchy within groups like they would do in fully natural conditions