They have carried cavalries into the battlefields, cultures exchanged and civilizations bloomed riding on their back into a new future, but how did the horses do it? They have great stamina, substantial intelligence, and cover long distances on little sleep. But how? When do they rest, actually? Do horses sleep with their eyes open? After all, you don’t often see them taking leisurely naps.
Horses have a reputation unlike any other animal, and rightfully so. They are the heroes of several folk tales and epic poems, where their untiring resolves rival their human counterparts. But unlike humans, they do not lie down for a good 7 – 8 hour sleep to refuel themselves for their next adventure. You can find them dozing off in the standing position during any part of the day. But how exactly do they rest, and if they actually do sleep with their eyes open, are the question we will explore below.
Do Horses Sleep With Their Eyes Open?
The short answer is yes, they do sleep like that. But if you extend this a bit, you will find that they rest by switching between a light nap and deep sleep. Horses spend anywhere from 3 – 5 hours a day taking these light naps. These kips are taken in the standing up position, and the phenomenon is so well-known that it even has a name for it, the stay apparatus.
Since it is a light nap for the horse to jerk awake from, it can happen with the animal’s eyes open (droopy) or closed. It means you may or may not find your horse sleeping with partially open eyes. To be able to tell if he is dozing off, all you need to do is to focus on their posture. If they are leaning to one side, with a hind leg bent and their body weight supported by one leg, they are most certainly recharging themselves with a short kip.
Horse Sleep Behaviors
Now that we know horses can sleep with or without closing their eyes, it is prudent to learn in a little more detail about equine sleep patterns.
● Power Naps
Though domesticated over thousands of years, horses retain several of their wild traits. In the wild, these strong and meaty animals were hunted by animals of prey. As a defense mechanism, they developed alertness and quick reflexes, even in their sleep. Surprisingly, they do not need as much sleep as humans.
They switch between naps and deep sleep to rest their bodies. The kips are taken in the “stay apparatus,” where the tendons and soft tissues come together to lock one hind leg in an upright position while the muscles in the remaining limbs relax.
● Deep Sleep
The horses do not really have blocks of deep sleep and light naps; instead, these are cyclical patterns where the horse may move from stages of alert wakefulness to drowsiness and eventually deep sleep, technically called the REM (rapid eye movement). The sleep cycle does not always progress directly to deep sleep, and even when it does, it is still cyclical, meaning the animal moves back and forth from REM to drowsiness, then alert wakefulness.
With an overall 3 – 5 hours of average daily sleep, the nighttime cycles last only 30 to 40 minutes. It is important to note that while napping can occur in the standing position, the deep sleep where horses truly rest, relaxing all their muscles without watching their backs, can only happen while lying down. If a horse is unable to lie down due to disturbance or the absence of preferred bedding, it will experience sleep deprivation.
● Sleeping Posture
We have already learned that horses sleep in both standing and lying positions. One of the reasons for the two postures is their need to remain alert as they evolved from prey-migratory ancestors in the wild. While the stay apparatus helps them keep their position without falling over, there is another benefit in lying down less often. Horses are huge; if they do sleep lying on the ground for longer hours, it may put a lot of pressure on their vital organs, constrict their blood flow, hurting them in the process. Also, standing up can take time and could prove lethal in the wild, their original habitat, where they were preyed upon.
● Herd Sleeping
Horses depict a strong herd behavior, where they would rather feel secure in a group of horses than isolated in an enclosed barn. This again stems from their wild instincts, where the herd sleeps in a group as the guard horse watches out for them, scanning for possible danger to alert its fellows. As a result, solitary horses do not experience as much deep sleep as those in a group. When they do get to live in groups, as in barns or stables, they automatically take turns to stay guard and ensure the rest of them are safe.
● Sleep Routine
So far, we know that horses tend to sleep in cycles of light naps and deep sleep, spread out throughout the day. But that does not say anything about them being nocturnals or diurnals. They fall in a third category, the cathemeral, that is to say, a sleep pattern that does not conform to the two aforementioned patterns. Horses simply go through cycles of eating and resting, whereby the active hours are influenced by external factors such as the season and food availability.
Do horses sleep with their eyes open? The answer is yes, horses do sleep with droopily open eyes, thanks to their wild instincts for safety. Horses sleep in a four or five-stage cyclical sleep pattern, where they move between states of dozing to slow-wave sleep and finally deep sleep. The initial napping can occur while standing, with sometimes close, other times open eyes, but the deep sleep can only occur while lying down.
Horses can suffer from sleep deprivation if they do not get enough deep sleep. Horses feel more secure when in a herd, with one horse standing guard while others rest. Horse sleep patterns may be influenced by external factors; therefore, care should be provided to ensure they get sufficient rest time. Sleep time varies between foals, adults, and senior horses, where the young spend half their day resting, adults taking shorter breaks while the older guys again sleep for longer durations.