Ever gone to catch your horse and wondered if they were asleep or dead?
That may sound like an extreme question, but to achieve REM sleep horses need to either lie flat out on their side, with their legs outstretched or in sternal recumbency. During REM sleep the body is very still and the eyes move rapidly (REM actually stands for Rapid Eye Movement). Horse owners often have a momentary panic when seeing their horse in this state when they haven't responded to their call.
Horses, like us, have several stages of sleep, but in sharp contrast to us they only sleep for around 4-5 hrs in a 24hr period. They can doze standing up but they do also need to lie down to achieve the deeper phases of sleep. It is believed that a minimum of 30 mins of REM sleep is necessary per day for horses to avoid becoming sleep deprived. This deep stage of sleep is essential - the body repairs itself, the immune system is strengthened and memories are consolidated, so this stage of sleep may be vital for learning.
We all know how awful it feels not to get enough sleep, so we need to ensure our horses sleep well too. Sleep deprivation can really affect a horse's behaviour - they may become anxious, spooky or even aggressive - and understandably so.
In a natural environment horses would have a friend to watch over them and keep an eye out for any potential danger while they sleep. So make sure your horse has friendly horse company - this will go a long way to ensuring your horse sleeps well. They also need plenty of room, so if they are stabled ensure they have a clean, comfortable bed and enough room to lie out flat.