How Do Horses Sleep?

Horses sleep both standing up and lying down. Most of their sleeping time is spent standing, which is crucial for their survival because it enables them to quickly escape predators. Sleeping while standing is possible because horses have a stay apparatus, a system of tendons, ligaments, and muscles that stabilizes the leg joints, essentially locking the legs in place and permitting sleep in an upright position. Horses enter a light sleep phase while standing, which is sufficient for their daily rest needs.

For deep sleep, specifically for REM (rapid eye movement) sleep, horses need to lie down. Similar to humans, in horses REM sleep is associated with dreaming and memory consolidation and is crucial for overall health. Horses lie down only for short intervals, usually multiple times a day, totaling between one and three hours. During these times, they often have a companion horse standing nearby to keep watch for predators or other threats.