If you've ever passed by a field of horses at night, you've probably noticed that they rarely lie down to sleep. So why do these mammals sleep standing up?
The answer is one of survival: Horses slumber while standing to balance their need for sleep against the ever-looming threat of predators.
Horses come from a long line of prey animals in the family Equidae, and sleeping on their hooves is an adaptation against predation. "Standing gives them a literal jump on predators and a better chance of getting away than if they were [lying] down,"Karen Waite, an equine specialist at Michigan State University, told Live Science in an email.
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Simply put, horses are big animals, and it takes time and energy for them to get off the ground. A standing horse is therefore much better able to run away when roused from sleep. According toBBC Science Focus, the same goes for other large prey herbivores, such as zebras, bison, elephants and giraffes, all of which are capable of sleeping on their feet.
Horses have specialized anatomical features that enable them to stay on their hooves while catching some z's. These features, known as a "stay apparatus" include a series of tendons and ligaments — soft tissues that connect muscle to bone, and bone to bone, respectively — that run throughout both the forelegs and hind legs, according to Waite. When a horse relaxes its leg muscles, the stay apparatus ligaments and tendons act as tension bands that stabilize the shoulder, knee and ankle joints in the legs. This enables the horse to remain standing without having to maintain much tension in their muscles.
But while horses do most of their sleeping while standing, they do need to lie down for more restorative sleep. "Horses will spend most of their time sleeping standing up, but they don't actually reach full REM sleep when they're standing,"Sarah Matlock, a senior instructor of equine behavior at Colorado State University, told Live Science.During rapid eye movement (REM) sleep in humans— when a sleeping individual's eyes move rapidly under closed eyelids — dreaming can occur, and so muscles become temporarily paralyzed so we don't act out our dreams. During REM sleep,the brain also consolidates and processes new information for long-term memories. People who don't get enough REM sleep may experience problems with mental concentration and mood regulation, a weakened immune system and less cell growth.
Adult horses are often able to get by on as little as 5 hours of sleep per day, and they can get most of it while standing up. And while standing horses can achieve "slow-wave," or deep, dreamless sleep, but an adequately rested horse requires at least 25 minutes of REM sleep per day, which can only happen while lying down, Matlock said.
Because of this, horses must lie down every day. If they don't, they may experience sleep deprivation, which can be a serious health risk for a horse. For instance, putting it at risk of injury from falling, according to theAmerican Association of Equine Practitioners. "Horses that don't get enough REM sleep can be misdiagnosed with narcolepsy," Matlock said. "Like, they might fall over while you're riding them."
Because standing while sleeping is an adaptation to avoid predators, horses need to feel comfortable and safe before they are willing to lie down and sleep, Matlock said. In feral horse populations, if multiple horses lie down to get REM sleep at the same time, there will always be at least one horse that remains standing, likely to watch for potential predators.
"If they don't feel safe in their environment, or they don't have other horses with them, or if they're isolated, then they're less likely to feel safe enough to lay down to sleep," Matlock said.
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The answer is one of survival: Horses slumber while standing to balance their need for sleep against the ever-looming threat of predators. Horses come from a long line of prey animals in the family Equidae, and sleeping on their hooves is an adaptation against predation.
Horses have an amazing ability to be able to sleep standing up. But they do also sleep lying down. If you're a horse, you need to be able to do both. It's one of the mistakes lots of people make about horses.
Because they, like other herd species, know there's safety in numbers, and they let half their brain doze while they are standing up, while the other half remains on alert. But for their short REM sleep periods, they lie down.
Answer: Laying a horse down is very beneficial, and something I do with all my colts. It quiets the horse very quickly and gets him to use the thinking side of his brain. It's a very humbling experience for a horse. As prey animals with a flight-or-fight reaction, horses would always rather run from danger.
While cows can doze off and sleep lightly on their feet, when it comes to REM sleep, they lie down just like the rest of us. This is true not just of cows, but of most other large herbivores as well – horses, bison, rhino, and more.
Mainly because sleeping while lying down can be dangerous. It takes a bit of work for horses to get up, which makes them vulnerable to attacks by predators. To protect themselves, horses instead doze while standing.
This is why observers of the foaling process are cautioned to minimize interference during the birth process so it can proceed normally The mare may be standing or lying down as contractions begin, but she usually will lie on her side for the actual birth.
Horses can sleep with their eyes either closed or open, and somewhere in between, with their lids half-closed. Whether your horse's eyes are open or closed is likely an indication of how sound he is sleeping, with open eyes indicating a lighter sleep.
Similarly, Hanco*ck4 found that it was debatable if cows ever sleep; even at times of total rest they kept their eyes open except for very short periods—a few minutes at most—when they generally rested their heads on the flanks.
Has your horse ever laid their head on your back when you're picking out their feet, or rested their head on your shoulder when you're standing in front of them? If your horse does this, it could be a sign that they are comfortable and relaxed in your presence and they trust you.
This happens when the horse lies down spontaneously, enjoys his rest, and he's okay with you joining him. Or the other way around: you lie down, fully present in the moment, and the horse feels the need to lie down as well, together with you.
On average, most horses spend a combined total of five to seven hours a day sleeping. It is generally accepted that horses spend approximately 15% of their total sleep time in REM sleep. While some horses get two to three hours of REM sleep per day, all horses need at least 30 minutes.
Horses first lived in the open plains where their fight-or-flight instinct needed to be strong to escape predators. As a result, sleeping while standing up allows them to flee quickly when danger is sensed.
When a cow is awake her head is lifted from the ground while being supported by the neck. During NREM sleep a cow's head will appear to be in a similar position as when she is awake, but the head and neck will be motionless. During REM sleep the head could be resting back on the body or on the ground.
One of the main reasons horses need less REM sleep than humans is that horses can only achieve this state while lying down. It's difficult for horses to spend much time lying down because, in the wild, they must be prepared to flee from predators. Lying down is hard work for horses, too.
Sleeping upright is advantageous for large animals because they would be slow to lumber to their feet if attacked. For smaller animals the reduction in leg springiness outweighs this benefit. Horses, zebras and elephants sleep standing up. Cows can too, but mostly choose to lie down.
It's common during trail rides for horses to lie down because they get hot and sweaty and want to roll in the sand to itch themselves and cool down. Or, you'll be guiding your horse through a water crossing and he'll decide to take a quick dunk in the water to cool off.
If the horse is simply lying down, not rolling, it's okay to let them rest. If they are rolling frequently and you are not alone, try to get them on their feet and walking to prevent them from injuring themselves. If you are alone and can't handle the horse safely without getting hurt yourself, don't get in their way.
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Introduction: My name is Madonna Wisozk, I am a attractive, healthy, thoughtful, faithful, open, vivacious, zany person who loves writing and wants to share my knowledge and understanding with you.
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