Horses communicate through body language. Horses grazing in a pasture can pick up on another horse's emotions through subtle changes in movement or stance. A dominant horse lifts its head with its chin up and its ears folded back to tell another horse to move. The dominant horse lunges forward if the other horse does not follow the orders.
A dominant horse may bite another horse in the shoulder or hindquarters if the horse does not follow the dominant horse's body language. Dominant horses push against other horses when they want them to move. If a horse does not move, the dominant horse increases the amount of pressure until the horse gives in to the pressure.
Horses change their facial expressions to communicate. Horses use their eyes and ears to express certain emotions. A horse often pins back its ears when it is frustrated.
Horses use their tails to communicate fear or excitement. When a horse hides its tail between its legs, it indicates fear. On the other hand, a horse with a spinning tail means that it is angry or annoyed at something. This is different from a horse using its tail to swat away insects. Horses raise their tails when they are excited as well.