Most of the time, horses use body language to communicate with each other. As horses communicate with each other, they can tell if they are playful, mad, or submissive. The more you are around horses, the better you will understand them and be able to know how they are feeling. Here are some common body language signs in horses and what each means:
Usually this means a horse is angry and is threatening another horse. When a horse is mad, the whites of its eyes may be visible and the teeth are usually showing. When a horse's ears are back, it can also mean that the horse is concentrating. If you watch horses that are running or competing, their ears will be back.
One or Two Ears Slightly Back
This means the horse is listening to something behind him. If the horse is being ridden, it means the horse is listening to the rider.
If the ears are held forward and the horse is attentive, it means the horse is listening. If the ears are tipped forward and stiff and the nostrils flare, it means the horse is scared or really interested in something.
Tail swishing usually means that the horse is agitated about something. You need to be cautious, because this can be followed by a kick. Tail swishing warns other horses to back off. There is another kind of swishing, too. Horses swish their tails to keep off flies and other insects. It is important to know the cause of tail swishing.
Horses will sometimes take off running and bucking across a field. This is a sign that a horse feels good and is in a playful mood. Its ears will be back, and it may grunt and squeal. Bucking can also mean that the horse is frightened. Young horses will often buck with riders the first couple of times they are ridden because they are unsure of the situation. Some horses will get in the habit of bucking because they have learned that they can unseat the rider. Bucking is not a sign of pain. Normally, a horse in pain will not want to move and, when asked, will refuse to move or move more slowly. A horse that is really afraid will not buck. It will rear up or, most likely, run. Remember, horses are flight animals.
Horses usually rear when they are playing. You will commonly see rearing in foals playing with each other or their dams. However, stallions will rear when they are fighting, and most horses will rear out of fear, especially when there is no escape. Horses that rear habitually or because they are mean are very dangerous to handle or ride.
From eXtension HorseQuest