How do I handle a horse that rears, and what causes rearing in the first place?

Rearing is one of the most dangerous behaviors a horse can develop under saddle, and it demands a thoughtful response rather than a reactive one. A rider who panics, grabs the reins, or leans backward when a horse rears is in serious danger of being flipped over on, which is one of the most catastrophic outcomes in horsemanship. Understanding what causes rearing is the first step toward addressing it safely and effectively, because rearing that originates from pain requires a completely different response than rearing that originates from a training gap or a learned evasion. Physical causes must be eliminated first. A horse that rears when asked to move forward, particularly under saddle, may be experiencing pain in its mouth from an ill-fitting bit or dental issue, soreness in its back from a poorly fitting saddle, hock or stifle pain that makes forward movement uncomfortable, or gastric ulcers that cause discomfort when the horse rounds and uses its back. A veterinary evaluation before any training intervention is not optional — it is essential. A horse that is in pain and rears when pressed will escalate rather than improve if the pain is not resolved. In horses where physical causes have been ruled out, rearing most often develops as a learned response to pressure from the front — specifically, rein pressure applied without a forward release. A horse that is held back by both reins simultaneously with no leg to push it forward has nowhere to go but up. The correction begins with restoring forward movement as the default response to leg pressure and eliminating the double-rein hold that removes the horse's forward option. When a horse begins to rear, driving it forward immediately — not backward — is the correct instinctive response. Forward momentum prevents the horse from committing to the rear. A single rein turned into a strong lateral movement redirects the horse's energy sideways rather than upward. Backward pressure at the moment of a rear is the most dangerous response a rider can make.