Horses, unlike domestic animals like cats and dogs, have never formed a voluntary symbiotic relationship with their human keepers. Horses are prey animals, which run in herds, and have a highly developed flight instinct in order to avoid becoming food for predators. Nonetheless, because their physiology is peculiarly suited to the accomplishment of a number of human-related jobs and entertainments, humans have domesticated horses and pressed them into service for centuries.
In order to make use of a horse, it must first be "broken" - that is to say, it must have its native flight instinct curbed to the point where it will acquiesce to human handling and follow commands. There are two general schools of horse breaking on the whole, one based on restraint, punishment and pain, and one utilizing efforts to obtain the animal's cooperation based on the way horses relate to each other.
One reads historical accounts and sees movie depictions of a horseman pursuing a feral horse, capturing it by force, and penning it. He then utilizes the restraint of a halter, which is tied to a snubbing post, in order to wear the animal down until, sweating, trembling, and blowing, it can be saddled. Once the saddle is in place, the horseman will climb aboard and signal a helper to release the restraint tying the horse's head to the snubbing post and try to stay in the saddle while the animal frantically attempts to dislodge him. To remain aboard a gyrating horse requires a good deal of athleticism and skill, not to mention a disregard for one's own bodily safety bordering on contempt. The attending commotion can be quite entertaining, and may attract the rapt attention of a number of standers-by, who may cheer the horseman in his efforts to subdue the wild beast. This, generally, is the origin of the sport of rodeo.
Further breaking techniques through hobbling a horse, tying up one or more legs, throwing the animal to the ground and preventing it from rising, beating it until it falls, and other inflictions of overwhelming force have been known to be employed.
When the horse is finally broken it will, to greater or lesser degree, suffer the attentions of humans without making a serious attempt to flee. It may then be trained further into one or a number of different disciplines.
A school of horse breaking which is gaining increasing popularity eschews violent means and makes use of what may be termed a horse's natural "body language"
Horses in the wild have developed a number of social behaviors and signals, which obtain to the survival of the herd. They appear to be uniform in horses around the world. There is a "pecking order" within the herd whereby senior animals exercise leadership and enforce discipline, and there are certain observable cooperative behaviors.
Perhaps the foremost and best-known advocate of the use of "horse language" as a training tool would be Monty Roberts, known the world over as the "horse whisperer." Roberts has a knack and a knowledge for curing horse fear and flight behaviors which he gained from observing herds of horses in the wild. Other proponents of the same or similar methods include John Lyons with his "round pen reasoning," Richard Shrake with "resistance-free training," Pat Parelli with "Parelli Natural Horsemanship" and others.
A commonality between the above-mentioned training methods is the way in which they advocate breaking a green or wild horse. In the wild, horses use a number of threatening or warning behaviors to drive other members of the herd into motion or warn them away. Likewise, certain motions and body postures are used to signal safety, acceptance, compliance and non-aggression. These signals have been adapted to human use in achieving a status between trainer and horse whereby the horse accepts the human as the "boss" or next above it on the pecking order, and yet is no more threatened by the presence of the human than by a senior horse.
The clearest and most fundamental pecking-order relationship in horse herds is that between mare and foal. Foals and young horses display subservience and a "don't hurt me - I'm harmless" message to other members of the herd by drawing the corners of their mouth back and open - creating an almost "keyhole" effect at the corners of the mouth, chewing dramatically, and lowering their head. Mares exhibit this same behavior (among others) to signal acquiescence to a breeding stallion. In mature horses, a less dramatic chewing motion, lowered head, and cautious approaching walk signals simple acquiescence. A mare will discipline and reassert her dominance over a misbehaving foal by raising her head and tail, and moving aggressively toward it. If it fails to retreat, she may make eye contact as a further threat, bite it at the rump or withers, or even resort to a mild kick. She will keep the foal at a distance and keep it moving away with these actions until it offers to return meekly with lowered head and chewing motions, indicating submission. She will in turn accept the contrite foal with her own lowered head, turning sideways, and perhaps engaging in mutual grooming. The pecking order is firmly established when she moves slowly away and the foal follows at her shoulder no matter which way she turns. Roberts calls this point in the relationship "join up."
A senior mare or "herd mare" will assert her dominance over the other mares in the herd in much the same way.
Non-violent horse-breaking begins in similar fashion, as the human attempts to attain the "herd mare" position relative to the horse being broken, while offering it no cause to believe its life is in danger.
The activity will take place in a pen, usually a round pen, large enough to permit free movement of trainer and horse, but too small to allow the horse to move far enough away that it can ignore the actions of the trainer. The trainer will lead the animal into the center of the pen and release it, driving it away with motions of a visual "threatener" such as a hat, whip, coiled rope or other visually obvious object. A coiled rope is often preferred. The trainer will keep the horse in motion by continuing to swing the rope in its direction, and will start, stop, and control the pace of the horse's movement by altering body position and the motion of the threatener. He may accompany these motions with verbal commands to begin to build an association in the horse's mind between the command and the movement. At no time will the trainer use eye contact, as this is a challenge to a horse. A rounded silhouette on the part of the trainer, a sign of safety to the horse, may be maintained.
From time to time, the trainer will allow the horse to stop. If it faces away, it is still rejecting the trainer. If it faces inward with head high, it is defiant or at best cautious or curious. It has not accepted trainer as boss. Eventually, the horse faces inward when it stops, head lowered, making chewing motions. It is submitting. The trainer is advised at this point to present his shoulder to the horse, and to create a markedly rounded silhouette, eyes averted. This is an invitation. If the horse approaches and stands at the trainer's shoulder, head still down, he has submitted. The trainer may stroke the horse's withers, another horse-to-horse comforting gesture. If the trainer moves off and the horse stays right on his shoulder, "join up" has occurred.
When the horse is in the habit of submitting to the trainer, blanket and saddle will be introduced gradually. The horse will be offered these items to see, sniff, and feel, and may have them rubbed on the sides of his barrel. Eventually, when the saddle can be put on and cinched without objection from the horse, more round pen work will be done with the saddle on until the horse is accustomed to it. At this point, the trainer may grab a handful of mane as a safety precaution, and stand in first one stirrup and then the other until the horse accepts him in a position that is higher than the horse's head. This is important, as predatory cats may attack from above, and horses are sensitive to living creatures above and behind their heads. Having been accepted in each stirrup, the trainer may hang himself belly-down across the saddle, eventually to rotate into a sitting position, facing forward, with both feet in the stirrups. If the horse accepts this, and responds to urgings to move forward without resorting to flight, he is broken. A horse broken in this fashion tends to develop a lifelong cooperative working relationships with its handlers.