It’s true, horses not only sleep lying down, they also rest standing up. They only lie down for about an hour a day, while they get a deeper sleep, the rest of the sleep time they stay on their feet.
This is because in nature, in their wild state, they are prey and have the instinct to flee from their predators. Sleeping standing up is a survival mechanism for staying alert. If they are lying down, they become more vulnerable and take longer to escape. The seconds it takes to get up can make the difference between surviving or being caught by the predator.
But how is it possible for them to sleep standing up?
Horses have an anatomical mechanism in their hind limbs that allows them to sleep standing up. It is a system that, when they fall asleep, blocks the knee joint, which is why they are able to relax without falling.
What usually happens is that the horse blocks only one of the limbs, while the other relaxes. It is for this reason that, many times, we see the horse resting on only one foot, keeping the other relaxed and the hips lowered.
Usually horses sleep, in total, about 3 hours a day, which may vary depending on age or tiredness. Foals usually sleep more hours, and in adulthood, when they are more tired, you can find them resting longer.
Given their survival instinct, feeling safe is a key point in getting them to sleep. For this reason, it is important to ensure a safe environment for horses to rest long enough and thus maintain their well-being.