Why does a horse’s lip tremble?

Sometimes you might see a horse standing quietly, with his lower lip slack and trembling. What does it mean? When we see this in a human we know that person is trying not to cry.

Luckily that’s not what’s going on here, and the answer is very simple. That quiet horse is peacefully snoozing. The quivering lip is a sign that he’s comfortable and relaxed. It’s just the same as a human mouth falling open when they’re asleep. And just as a human will quickly close theirs when they wake up and realise, a horse will too.

Tip: When you do see that trembling lower lip, approach the horse quietly and gently so as not to startle and scare him.