Sleep Patterns of Horses

I know that this blog is generally focused on human sleep and dreams, but sleep behavior of other species can just be so damn interesting.  Also, there might be one or two of you that own horses or soon will own horses and need to know their basic behaviors, like what horses do when they sleep.

For example, it is normal for horses to not sleep as much as dogs, cats or people.  Foals tend to sleep laying down more often than adults.  Horses, like people, can also suffer from sleep deprivation.

Since horses are prey animals, they evolved to spend most of their time awake in order to respond quickly in case a predator made an appearance.  Even though horses have been domesticated for thousands of years, this trait has still not been removed.  It’s rare for a horse to lay down for the deepest possible sleep unless the horse feels that the area is safe enough for him to do so.

Standing Up

Not many studies have been made on the sleeping behavior of horses, but one unscientific one was done by photographer Robert Vavra. During his decades of photographing horses, he got to see many horses in a feral or semi-feral state.  He noted in Such is the Real Nature of Horses (1979) that horses sleep in three body positions.

The first is the sight most of us are familiar with: a horse asleep while standing up.  The head is down, the lower lip drooped and one hind leg is cocked. The forelegs do not need to be cocked because they can stand the weight.  This is the lightest form of sleep because they can quickly run away should danger threaten.  Horses approached in this position need to be talked to softly so that they wake up before you touch them, otherwise the horse may panic.

Lying Down

The other two body positions of sleeping horses include lying on the chest with the head up (although the jaw may be touching the ground) and lying flat out on one side.  Foals often need to sleep lying down on their sides because their bodies use up so much energy for growing.  Horses can only lie on their sides for about twenty minutes at a time.  The blood them begins to pool on their side they are lying on and the pain wakes the horse up.

Horses need stalls large enough for them to lie down in and get this deep sleep.  Many horses in this deep sleep snore or show signs of dreaming.  Horses waking up from this type of sleep will be quite groggy, as opposed to horses that sleep standing up.  When horses live in herds, they take turns lying down to sleep while others keep watch.

Sleep Deprivation

Horses need about six hours of sleep per night and tend to catch naps during the day.  If a horse is stressed out, she cannot sleep.  After a few days, the horse may begin suffering from sleep deprivation.  Not much is known about sleep deprivation in horses, but some British horse clicker trainers believe many domesticated horses trained with harsh methods or horses that live alone are most prone.

Sleep deprivation can harm the horse’s immune system and general well-being because they are on such constant stress.  The horse may suddenly fall asleep in bizarre times like getting tacked up or just before being fed because their bodies are in desperate needs of REM sleep.  The horse may fall asleep standing but suddenly begin to collapse.  The fall wakes the horse back up.

Image of sleeping thoroughbred foal by Daita for Wikimedia Commons.