Horses sleep standing up and laying down. When a horse sleeps, he lays down in a comfortable, safe spot and goes into a deep slumber cycle called rapid eye movement (REM). However, a horse can also take several, short naps throughout the day in a standing position. This is a much lighter sleep made possible because of a horse's stay apparatus in his legs.
Amount of Sleep
It is estimated that adult horses stand and rest anywhere from 4 to 15 hours a day, with the head down in a diffused drowsiness. The sleep habits of a horse in captivity or nature largely depend on the weather, breed, age, or the activity at the barn or the environment. According to Dr. Bertone, Professor of equine medicine at Western University of Health Sciences, College of Veterinary Medicine, horses vary in how long they can go without lying down. "One thing is certain," explains Bertone. "At some point horses have to lie down to go into paradoxical sleep. Some horses can't go more than two weeks while others seem to go months." (References 6)
Lying down is more emotionally and physically stressful for a horse than standing. The horse's own weight can cause stress. According to Dr. Joe Bertone, all horses will only lie down when they feel safe. "Some horses feel fine no matter where they are and others are timid and require a sentinel horse around to guard from threatening activity." Many prefer lying down in a dry, sheltered area that is quiet. It is only with these things in order that a horse can experience slow-wave, REM sleep as he stretches out on his side or lies on his sternum.
A slumbering horse is easy to recognize. His head and neck droop, eyes close and ears relax. According to Dr. Bertone, the amount of time a horse sleeps standing up during the day varies according to breed and personal needs. When standing, the horse carries its weight on both forelegs and one hind leg. The other hind leg simply relaxes with the hoof up on its toe. This is because of the stay apparatus, which allows a horse to stand and exert little energy while staying relaxed in this locked position. A standing horse never gets the full extent of sleep that a horse lying down does.
Sleep deprivation happens when a horse desperately needs paradoxical sleep. Sometimes lyme disease or pain, such as musculoskeletal or abdominal pain, prohibits a horse from getting the sleep he needs. Other times, the horse may be experiencing aggression issues or anxiety, or lacks an alpha mare nearby who can give the horse the confidence to lay down. According to Dr. Bertone, physical signs of sleep deprivation include weight loss and marks or scars on a horse's fetlock from collapsing and catching himself. Also, a crabby horse could be a sign of environmental issues, he explains. "Sometimes simply giving a horse a larger stall or bringing him inside can automatically fix sleep issues."
- Equine Vet Chiropractor: Equine Stay Apparatus
- Penn Veterinary Medicine: Equine Maintenance Behavior: Feeding, Drinking, Coat Care and Behavioral Thermoregulation
- The Horse: Understanding Equine Sleep Deprivation
- Equi Search: How Horses Sleep
- Equi Search: How Horses Sleep Pt. 2 -- Power Naps
- Joe Bertone; Professor of equine medicine; Western University of Health Sciences College of Veterinary Medicine
- David De Lossy/Photodisc/Getty Images