Rodeo horses buck because of a combination of natural instinct, selective breeding, and a piece of equipment called a flank strap that encourages them to kick out with their hind legs. No single factor explains the behavior on its own. The explosive bucking you see in saddle bronc and bareback events is the result of genetics, training, and physical cues working together during an eight-second ride.
Breeding Creates Bucking Instinct
The most important factor is one most people don’t think about: genetics. Bucking horses are purpose-bred athletes, much like racehorses are bred for speed. Stock contractors (the companies that supply animals to rodeos) run dedicated breeding programs, pairing mares and stallions with proven bucking ability to produce offspring that naturally want to buck. The Bucking Horse Breeders Association even offers parentage and DNA testing services so breeders can verify bloodlines and refine their programs over generations.
This matters because not every horse will buck hard enough for rodeo competition, no matter what equipment you put on it. Horses that lack the genetic drive simply won’t perform. The ones that do buck tend to show the instinct early, often as young, unbroken colts. Contractors watch for horses that buck with power, height, and unpredictable direction changes, then selectively breed those animals to pass the trait forward. A top bucking horse can be worth tens of thousands of dollars precisely because that combination of athleticism and temperament is hard to reproduce.
What the Flank Strap Actually Does
The flank strap is the piece of equipment that draws the most questions and the most misconceptions. It’s a strap placed around the horse’s flank, just in front of the hind legs, roughly where a belt sits on a person. Its job is to encourage the horse to kick out behind itself rather than rear up, which produces the dramatic hind-leg action audiences associate with bronc riding.
A persistent myth claims the strap is tied around the horse’s testicles. It isn’t. The strap sits well forward of the genitals, on the soft tissue of the flank. At professional rodeos, flank straps are lined with sheepskin or neoprene to prevent chafing or irritation. The strap creates a sensation of pressure that the horse instinctively tries to kick away from, amplifying the bucking motion that’s already bred into the animal. When the ride ends and the strap is released, the horse typically stops bucking almost immediately, which itself shows the strap is a trigger rather than a source of ongoing distress.
Think of it this way: the flank strap doesn’t make a calm horse go wild. It takes a horse that already wants to buck and shapes the direction and style of its movement. A horse with no bucking instinct will mostly just run or trot with the strap on.
The Role of the Rider
The rider’s weight and movement also influence how a horse bucks. A 150- to 200-pound person shifting on its back is inherently irritating to a horse that hasn’t been trained to accept a rider calmly. Bucking horses are not “broken” the way a riding horse is. They’re allowed, even encouraged, to retain their natural flight-or-fight response to something on their back. When a rider climbs into the chute and the gate opens, the horse’s instinct is to get the weight off by any means necessary.
Spurs also play a role. In bronc riding, riders are actually required to spur the horse to score points. But rodeo spurs are designed to be non-injurious. Rowels (the spinning wheel at the end of the spur) must roll freely and typically have five or more dull points, which prevents them from cutting or penetrating the skin. The spurring action irritates the horse enough to keep it bucking aggressively but doesn’t cause the kind of sharp pain a fixed or sharpened spur would.
Why Some Horses Buck Harder Than Others
Just like some people are more athletic or more reactive than others, bucking horses have individual personalities and physical traits that determine their style. Some spin. Some leap straight into the air. Some drop their front end violently and kick their hind legs skyward. The most prized rodeo horses combine raw power with unpredictability, making it nearly impossible for a rider to anticipate the next move.
Horses are scored alongside the rider at professional rodeos, and the best bucking horses become famous in the sport. An animal that bucks in a flat, predictable pattern won’t score well and won’t last long in competition. The ones that earn top marks tend to change direction mid-buck, get significant height off the ground, and sustain intensity for the full eight seconds. These traits are partly genetic, partly temperamental, and partly a product of how the horse has been managed throughout its career. Contractors who handle their horses well, keeping them healthy, fit, and not overworked, tend to get better performances.
Veterinary Oversight at Rodeos
All rodeos sanctioned by the Professional Rodeo Cowboys Association are required to have a licensed veterinarian on-site during performances. Horses are inspected before competition, and stock contractors must follow PRCA guidelines for animal care or face penalties and fines. This applies not only to bucking broncs but also to saddle horses used in timed events and pickup horses that help cowboys dismount safely after a ride.
Horses that show signs of lameness, illness, or injury are pulled from competition. The financial incentive aligns with the welfare incentive here: a top bucking horse represents a significant breeding and training investment, so contractors have strong reasons to keep their animals in peak condition.
What Happens After a Bucking Career
Bucking horses typically compete for several years, with careers that can span a decade or more depending on the animal’s health and performance. Unlike racehorses, which face intense physical strain at young ages, bucking horses work in short bursts and may only perform a handful of times per month during the season. This relatively light workload, combined with their value as breeding stock, means many retire to breeding programs where they continue producing the next generation of rodeo athletes. Mares are especially valuable in retirement for this reason. Horses that aren’t used for breeding are often retired to pasture, either on the contractor’s property or through equine retirement facilities that specialize in long-term care.