Horses with a naturally high head, like Arabians, normally have very little tendency to resort to bucking to solve their problems. To deal with Zum’s bucking, I need to raise his head. A horse cannot buck as long as his head is up. In order to buck, a horse needs to arch his backbone and that is mechanically impossible when his head is elevated. It makes sense. But Zum uses bucking as a means to escape from a situation. He gives no warning that he is going to buck.
