Why do horses yawn and curl their top lip?

Hi! 😄🐴

🐴 When horses smell something, they draw in air carrying scent particles, which land on the olfactory membrane right at the back of the nasal cavities. From there, nerves carry signals that drive reactions linked to things like flight or reproduction.

🐴 Certain smells make horses perform the flehmen response, lifting the top lip and breathing the scent in, which also carries the particles into the vomeronasal organ (also called the Jacobson's organ). Nobody is quite sure why horses do this, but it is often linked to strong smells, or to a stallion smelling another horse's urine or droppings, for example. It most likely helps horses gauge how the others around them are doing. Stallions, for instance, often do it when they smell the urine of a mare in season.

🐴 Yawning can come down to several things. Horses can of course simply be tired. But yawning is also part of how they communicate. There is something called calming signals, which horses use to ease the mood around them and show they pose no threat. Yawning is one such signal. A horse yawns at another to show it does not want any trouble and that all is calm.

🐴 Some horses yawn before they are bridled. It can signal that they find something a little unpleasant, but there are also individuals who yawn when they are a bit keyed up and getting themselves ready.

🐴 Signals and behaviours are a tricky business. It is important to get to know your horse and stay alert to changes in behaviour and what might lie behind them.

For more on calming signals, have a read of this: https://www.adlibris.com/se/bok/language-signs-and-calming-signals-of-horses-9781138070158