This dramatic display shows a man struggling to control a rearing horse. But why can humans control horses at all, when horses are so much bigger and stronger than humans?

Horses are creatures of instinct. But certain instincts work in our favor. The way horses naturally evolved to eat, mate, form family groups, and accept the authority of herd leaders makes them receptive to taking orders from humans as well.

Lipizzaner horse practicing a jump.

AP/World Wide Photos

Leaping Lipizzaners

Lipizzaner horses perform incredible acrobatic displays. But even these highly stylized movements are based on instinctive behavior. Trainers start with a movement like kicking an attacking animal and gradually train the horse to do it in a different way, until it resembles ballet.

Tough to Train

Why do we ride horses, but not their close relatives, zebras? Male Grevy's zebras fight over territory, so they can't be kept in the same corral. Horses have no fixed territories, wandering constantly to graze, and fight less over turf. Zebras are also notorious for biting--in fact, zebras injure more zookeepers than tigers do.

"Breaking" Vs. "Gentling"

One way to train horses is through brute force and intimidation. But some trainers instead appeal to a horse's natural instinct to follow a leader. For example, instead of beating a horse until it is afraid to disobey, a trainer might chase it away. Horses don't like being isolated from the herd, so the animal returns, seeking permission to end its banishment. From then on it accepts the human trainer as herd leader and follows instructions.