A stallion is a male horse that has not been gelded (castrated). Stallions will follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck, as well as a somewhat more muscular physique as compared to female horses, known as mares, and castrated males, called geldings.
Temperament varies widely based on genetics, and training, but because of their instincts as herd animals, they may be prone to aggressive behavior, particularly toward other stallions, and thus require careful management by knowledgeable handlers. However, with proper training and management, stallions are effective equine athletes at the highest levels of many disciplines, including horse racing,horse shows, and international Olympic competition.Contrary to popular myth, the stallion is not the leader of a herd, but defends and protects the herd from predators and other stallions. The leadership role is held by a mare, known colloquially as the "lead mare" or "boss mare." The mare determines the movement of the herd as it travels to obtain food, water, and shelter. She also determines the route the herd takes when fleeing from danger.
The term "stallion" is also used to refer to males of other equids, including zebras and donkeys.
When the herd is in motion, the dominant stallion herds the straggling members closer to the group and acts as a "rear guard" between the herd and a potential source of danger. When the herd is at rest, all members share the responsibility of keeping watch for danger. The stallion usually is on the edge of the group, to defend the herd if needed.
There is usually one dominant mature stallion for every herd of horses. The dominant stallion in the herd will tolerate both sexes of horses while young, but once they become sexually mature, often as yearlings or two-year olds, the stallion will drive both colts and fillies from the herd. Colts may present competition for the stallion, but studies suggest that driving off young horses of both sexes may also be an instinctive behavior that minimizes the risk of inbreeding within the herd, as most young are the offspring of the dominant stallion in the group. In some cases, a single younger mature male may be tolerated on the fringes of the herd. One theory is that this young male is considered a potential successor, as in time the younger stallion will eventually drive out the older herd stallion.
Fillies usually soon join a different band with a dominant stallion different from the one that sired them. Colts or young stallions without mares of their own usually form small, all-male, "bachelor bands" in the wild. Living in a group gives these stallions the social and protective benefits of living in a herd. A bachelor herd may also contain older stallions who have lost their herd in a challenge.Domesticated stallions are trained and managed in a variety of ways, depending on the region of the world, the philosophy of the owner, and the temperament of the individual stallion. In all cases, however, stallions have an inborn tendency to attempt to dominate both other horses and human handlers, and will be affected to some degree by proximity to other horses, especially mares in heat. They must be trained to behave with respect toward humans at all times or else their natural aggressiveness, particularly a tendency to bite, may pose a danger of serious injury.
Other stallions may directly challenge a herd stallion, or may simply attempt to "steal" mares and form a new, smaller herd. In either case, if the two stallions meet, there rarely is a true fight; more often there will be bluffing behavior and the weaker horse will back off. Even if a fight for dominance occurs, rarely do opponents hurt each other in the wild because the weaker combatant has a chance to flee. Fights between stallions in captivity may result in serious injuries; fences and other forms of confinement make it more difficult for the losing animal to safely escape. In the wild, feral stallions have been known to steal or mate with domesticated mares.
For this reason, regardless of management style, stallions must be treated as individuals and should only be handled by people who are experienced with horses and thus recognize and correct inappropriate behavior before it becomes a danger. While some breeds are of a more gentle temperament than others, and individual stallions may be well-behaved enough to even be handled by inexperienced people for short periods of time, common sense must always be used. Even the most gentle stallion has natural instincts that may overcome human training. As a general rule, children should not handle stallions, particularly in a breeding environment.The other general method of managing stallions is to confine them individually, separately from other horses, sometimes in a small pen or corral with a tall fence, other times in a stable, or, in certain places, in a small field (or paddock) with a strong fence. The advantages to confinement include less of a risk of injury to the stallion or to other horses, controlled periods for breeding mares, greater certainty of what mares are bred when, less risk of escape or theft, and ease of access by humans. Some stallions are of such a temperament (or develop vicious behavior due to improper handling) that they must be confined and cannot be kept in a natural setting, either because they behave in a dangerous manner toward other horses, or because they are dangerous to humans when loose.
Management of breeding stallions usually breaks down into one of two basic types: confinement or "isolation" management, and "natural", "herd", "pasture" or "harem" management. Sometimes a stallion may periodically be managed in both systems, depending on season of the year.
The drawbacks to confinement vary by the actual method used, but lack of exercise can be a serious concern; stallions without sufficient exercise may not only become fat, which may reduce both health and fertility, but also may become aggressive or develop stable vices due to pent-up energy. If stallions are kept in complete isolation from other animals, they may develop additional behavior problems. Conversely, some stallions within sight or sound of other horses may become aggressive or noisy, calling or challenging other horses. In any case, stallions kept alone require a careful balance of nutrition and exercise for optimal health and fertility.Attitudes toward stallions vary between different parts of the world. In some parts of the world, the practice of gelding is not widespread and stallions are common. In other places, most males are gelded and only a few stallions are kept as breeding stock. Horse breeders who produce purebred bloodstock often recommend that no more than the top 10 percent of all males be allowed to reproduce, to continually improve a given breed of horse.
As a general rule, a stallion that has been isolated from the time of weaning or sexual maturity will have a more difficult time adapting to a herd environment than one allowed to live close to other animals. However, as horses are instinctively social creatures, even stallions are believed to benefit from being allowed social interaction with other horses, though proper management and cautions are needed.
People sometimes have inaccurate beliefs about stallions, both positive and negative. Some beliefs are that stallions are always mean and vicious or uncontrollable, other beliefs are that misbehaving stallions should be allowed to misbehave because they are being "natural", "spirited" or "noble." In some cases, fed by movies and fictional depictions of horses in literature, some people believe a stallion can bond to a single human individual to the exclusion of all others. However, like many other misconceptions, there is only partial truth to these beliefs. Some, though not all stallions can be vicious or hard to handle, occasionally due to genetics, but usually due to improper training. Others are very well-trained and have excellent manners. Misbehaving stallions may look pretty or be exhibiting instinctive behavior, but it can still become dangerous if not corrected. Some stallions do behave better for some people than others, but that can be true of some mares and geldings, as well.A ridgling or "rig" is a stallion which has an unde-scended testicle. If both testicles are not descended, the horse may appear to be a gelding, but will still behave like a stallion.However, in many cases, ridglings are infertile. The condition is most easily corrected by gelding the horse. A more complex and costly surgical procedure can sometimes correct the condition and restore the animal's fertility, though it is only cost-effective for a horse that has very high potential as a breeding stallion.
In some parts of Asia and the Middle East, the riding of stallions is widespread, especially among male riders. The gelding of stallions is unusual, viewed culturally as either unnecessary or unnatural. In areas where gelding is not widely practised, stallions are still not needed in numbers as great as mares, and so many will be culled, either sold for horsemeat or simply sold to traders who will take them outside of the area. Of those that remain, many will not be used for breeding purposes.
In Europe, Australia, and the Americas, keeping stallions is less common, primarily confined to purebred animals that are usually trained and placed into competition to test their quality as future breeding stock. The majority of stallions are gelded at an early age and then trained for use as everyday working or riding animals.