The mounts used are called 'polo ponies', although the term pony is purely traditional and the mount is actually a full-sized horse. They range from high at the withers, and weigh . The polo pony is selected carefully for quick bursts of speed, stamina, agility and manoeuvrability. Temperament is critical; the horse must remain responsive under pressure and not become excited or difficult to control. Not to mention that it requires intelligence to know what is happening in the field, follow the game and have a notion of the other players, the other horses and the changes that may occur. Many are Thoroughbreds or Thoroughbred crosses. They are trained to be handled with one hand on the reins, and to respond to the rider's leg and weight cues for moving forward, turning and stopping. A well trained horse will carry its rider smoothly and swiftly to the ball and can account for 60 to 75 percent of the player's skill and net worth to his team.