We all know horses can act goofy on occasion, both amusing and confusing their caretakers. But which, if any, of these equine actions are considered normal? One way for horse owners to find out is to study the 11 primary categories of equine behavior as outlined in My Horse University’s online Horse Behavior and Welfare Course, based out of Michigan State University.

“Of course I am biased, but I think there is nothing in the world more important to the average horse owner better understanding their horse and, in turn, enhancing their horse’s welfare, than to know more about horse behavior,” says Dr. Camie Heleski, coordinator of the Michigan State University Horse Management Program and lead instructor for the online behavior course. “[That means] everything from understanding that the horse evolved to eat lots of reasonably low-quality forage through the vast portion of the day … to always remembering that the horse evolved as a creature of prey, hence their first reaction is always to flee from a potential source of danger.”

Here’s a look at these categories, with comments from some behavioral experts:

Ingestive Behavior refers to a horse’s eating and drinking habits. Given the choice, as most horse owners know, equines like to forage or graze most of the day. What is less commonly known is that they prefer to ingest many different species of plants, not merely grass or hay. This follows a pattern observed in wild horses and illustrated in experiments conducted by Dr. Debbie Goodwin, a lecturer in Applied Animal Behavior at the University of Southampton (United Kingdom) and honorary president of the International Society for Equitation Science (ISES) council.

“Horses have only been domesticated for around 6,000 years, and so much of their digestive physiology and foraging behavior has changed very little during domestication,” says Goodwin. “Owners can meet their horses’ nutritional and foraging motivational needs by providing a varied forage diet for their horses. There are many forages suitable for horses available on the market, so the variety offered can be tailored to meet the nutritional and workload requirements of individuals, and cater to their dietary preferences.”

She recommends contacting your local feed merchant for long-chop hay or haylages, plus short-chop, bucket-fed forages that are suitable for horses and that provide “a variety of physical shapes and textures as well as tastes and nutritional content.” Since these products are more common in Europe than in America, Dr. Christine Skelly, director of curriculum for My Horse University, suggests planting “a variety of grass and legume species in a pasture mix and/or feed mixed hay (grass and legume blend).” Be sure to offer only small quantities of novel forages at first, ensuring that your horse’s usual forage is also available.

Though well-fed horses are unlikely to ingest toxic plants, it is important to note that this is still a possibility. As for water, the old rule of making it available 24/7 is worth heeding, even though in the wild, horses only drink a few times a day.

What goes in must come out, and that is where Eliminative Behavior plays a role. Some horses are not particular about where they defecate or urinate, while others have preferred elimination areas, especially in larger pastures. (Horses are notorious for avoiding these soiled spots, but mowing and dragging will maximize utilization and help kill parasites, while rotating pastures will refresh these areas.)

In addition, stallions will defecate on other horse’s fecal piles, generally after smelling them. “Dung piles are used to signal the presence of a resident stallion,” explains Natalie Waran, senior vice president of the ISES council and head of the School of Natural Sciences at Unitec New Zealand. “Horses are not territorial about space, but stallions are protective of their mares! The constant piling of dung ensures that it remains fresh, and the pheromones strong. Other stallions may ‘over-mark’ by placing their dung over that of the resident stallion to try to claim ownership.”

“Curiosity killed the cat” applies to more than just felines. A horse’s Investigative Behavior–an outgrowth of its natural curiosity–can get it into trouble when checking out objects left within reach. Because of the risk of injury, horse owners should keep pastures and barn aisles free of such enticements.

Is a horse’s investigative behavior any indication of its intelligence? Not necessarily, according to Dr. Cindy McCall, professor and extension horse specialist in the Department of Animal Sciences at Alabama’s Auburn University. “I don’t know of any studies linking investigative behavior with intelligence in horses,” she notes. “And there are so many other factors [that] influence both investigative behavior (e.g., age, gender, management) and intelligence (e.g., type of test, reinforcers and reinforcement delivery system, previous experiences of the horse) that it would be difficult to draw conclusions about their relationship.”

Of course, investigative behavior can be turned to a training advantage with a little patience–like when using grain to lure a reluctant shipper onto a trailer. Rather than rushing the process, and risking a bad association, experts agree that it’s better to slow down and let the horse’s natural curiosity work for you.

Since horses are herd animals, chances are you’ve seen many instances of Social Facilitation (also called allelomimetic behavior). This refers to the tendency of animals in a herd to do the same thing at the same time, such as walk to the watering trough.

Vigilance is another example of social facilitation, one driven by the fact that horses are prey animals and thus keenly alert to signs of danger. Because of this, at least one horse in a herd will often stand lookout; or, if one horse adopts an alert posture, the others follow suit and go “on guard.” The classic example of social facilitation is when you’re on a trail ride and one horse spooks, triggering the same reaction in his companions. It doesn’t matter that only one horse has seen the source of danger; as far as they are concerned, this is a life-saving behavior, so better safe than sorry!

If you’ve ever doubted that horses care about each other, just watch the group fly-swatting and mutual grooming that goes on when they are turned out together. This is Care-Giving Behavior, or epimeletic behavior, and it’s important because it helps create social bonds. According to recent studies, “feel good” hormones are increased in horses that have undergone mutual grooming sessions, and horses also have preferred grooming partners. Another example of care-giving behavior is a mare nickering for her foal to move closer to her for protection from perceived threats.

By the same token, a young foal nickering for its dam or separated horses calling for each other are engaging in Care-Seeking Behavior (or et-epimeletic behavior).

Which begs the question: Do orphan foals–those hand-reared by humans–develop these same care-seeking and care-giving behaviors? “Orphan foals appear to function quite normally as long as they have been given early experience with other horses,” explains Waran. “It has been reported that they can develop too strong an association with humans if human [caregivers] are not careful; for example, there are reports of orphaned, hand-reared foals showing play and sexual behavior towards humans. In terms of their ability to mother,’ there appears to be no problem with this; hand-reared foals will show maternal behavior and will get better with time.”

Raging hormones during breeding season make Sexual Behavior nearly impossible to ignore. Equines are considered “long-day breeders,” which means that mares tend to begin cycling during early spring, are at their most fertile during the summer, and enter “reproductive quiescence,” or anestrus, during the colder months.

Among mares, sexual behavior is most obvious when they’re in estrus (heat), an event that lasts three to seven days and occurs roughly each 21 to 23 days during the breeding season. Though a mare’s cycle can be inconsistent, the telltale signs that she’s in heat include urinating frequently and/or lifting her tail and “winking” (opening and closing) her vulva. Only at the height of estrus will she actually accept a stallion for breeding. A mare’s sexual behavior can disrupt her training and competition schedule, which is one reason some people prefer geldings. Such behavior can be controlled through the administration of hormones, but this is costly and best discussed with your veterinarian.

If you elect to train a mare during her heat cycle, Dr. Andrew McLean, junior vice president of the ISES council and developer/manager of the Australian Equine Behaviour Centre, recommends doing so “sympathetically.” That means reducing all signals to light aids, he says, and ensuring that “she is in self-carriage and not running away/leaning on the bit or forced into an outline by strong hands.

“Mares are more sensitive than male horses and become defensive when harsh methods are used, so they need to be trained by fair and gentle methods,” he explains.

Young colts start exhibiting sexual behavior as early as six months of age, so it’s critical to keep them separated from female equines–including their own dams and siblings–until they are gelded (castrated). The later a male horse is gelded, the more he will behave like a stallion, even after the procedure.

A stallion’s sexual behavior is manifested in his marked interest in mares. He may become excitable, proclaiming his interest by vocalizing and dropping his penis when near a mare in heat. In addition, he will display agonistic (aggressive) behavior toward horses that he considers competition for those mares. A stallion must be taught from the outset to limit his sexual behavior to the breeding shed. Indeed, it requires careful handling and just the right amount of authority to keep a stallion from turning on his handler or behaving like a bully in general.

Of course, Agonistic Behavior isn’t restricted to stallions. Signs of aggression can range from a horse pinning its ears and lunging at the person tightening its girth to nipping, biting, wheeling and kicking. Horses kept in the same groups rarely exhibit more than a threatening display towards each other. By contrast, those in new social arrangements may engage in full-fledged aggressive encounters that could result in injuries. As horse owners, we’ve all witnessed the “pecking orders,” or Dominance Hierarchies, that evolve when horses are turned out together. In such social situations, horses are ranked from the most dominant to the most submissive, with behavior and body language reflecting those ranks.

Because each horse knows its place, this natural hierarchy actually helps minimize aggressive behavior in the long run. Of course, hierarchies can change with the situation; for example, the “top” horse at feeding time might not rank so highly in the competition for shelter. It’s also important to remember, when working in a group of horses, that the group dynamic takes precedence–and you could get caught in the crossfire!

Contactual Behavior is a type of behavior that is not as well developed in equines as it is in other domestic livestock. It involves the seeking of affection or protection through physical contact with other animals. One example is when horses huddle together for added protection from the elements.

As with humans, “all work and no play” makes for a dull and possibly unhappy horse! Equine Play Behavior–while not always recognized as a separate category–can be divided into object play, play fighting, locomotor play and sexual play.

In object play, the horse amuses itself with something such as a ball. Locomotor play is, according to the My Horse University course text, “simply the exuberant release of energy that can be seen when horses take off running across a field for no apparent reason, or when a fresh horse bucks a few times on the longe line.”

So there you have it: a brief look at why equines do what they do. With a little patience and understanding, we can use that knowledge to make their lives both happier and healthier.

My Horse University is a national online program for horse enthusiasts based at Michigan State University, one of the top U.S. universities in equine science and management. This program offers equine education courses and resources to help you achieve your horse-management goals.