Only sleeping

The pony lay flat and motionless as I approached it - with some concern. When I got close it jerked awake and scrambled to its feet as if disconcerted to have been caught unaware. 
Two other horses were grazing not far away. I have read that horses should never be kept on their own because they cannot surrender to sleep unless a companion animal remains on guard. This makes sense because a large prey animal is very vulnerable when off its feet. But does it mean that solitary horses are permanent insomniacs? I tried to find out and discovered that, while horses can doze on their feet, they do need to lie down to get  REM sleep.


"The reason horses can sleep while standing for most of their sleep cycle is because it allows them to quickly escape an attack by a predator without having to waste time standing up (which can be a slow process compared to a predator attack). The method by which horses stand while sleeping is called the "stay apparatus," and it's a system of ligaments and tendons that keep them upright with relative ease.
Horses also like using the buddy system for sleeping - where one horse watches over the others while they're sleeping. The role of watch-horse will rotate as each member of the herd gets the sleep they need, including lying down for necessary REM sleep. Many horses adopt this kind of rotation when they're in their home barn setting, either in a paddock or in a stall next to their regular neighbours."


So horses need noisy neighbours. Or neigh-bours. ( Sorry!)