Aggression in Horses
Dr. Linda Aronson
Grooming. Particularly sensitive spots with harsh implements.
Aggression Directed at Other Horses
Horses are herd-living animals, and allowing them opportunities to interact with other horses tends to promote good health and behavior. They will be less likely to engage in obsessive or stereotypical behaviors, such as cribbing or stall walking, if they can spend at least part of their day turned out either with other horses, or at least where they can observe them over the fence.
In general, horses in a group have a fairly loose dominance hierarchy. The more dominant horses are usually deferred to by the less dominant but, with any hierarchy, an animal may defer over some issues and stand up to a more dominant animal to protect more valuable resources. For a mare, this might mean defending her foal from bullying or injury. If the horses get their grain ration at turnout, a more submissive animal might defend this resource, but not hay. Some horses can definitely be bullies. They may move other horses around constantly so that the others cannot settle and graze, they may defend water or food piles from others, or they may show truly aggressive, antagonistic behavior to others.
Most of the fighting seen in an established group, however, tends to be play fighting. Domestic horses are more likely to engage in such shenanigans than their wild counterparts, where the behavior is usually restricted to young colts. While bites and kicks tend to be inhibited, they may still result in injury, whether intentional or accidental. Horses should be watched at turnout and separated if the play gets too rough. If one horse is consistently picking fights or acting the bully, he should be removed from the group, although it may be possible to integrate him into a group of more self-assured horses. Likewise, if one horse is always the scapegoat, he, too, should be removed and placed with more congenial companions, or allowed to watch the group from the safety of a different paddock.
Horses that have been raised in isolation from others of their species have a particularly hard time in groups, as do blind animals. They have not learned, or cannot see the signals of mood and intent being given by their peers, and are liable to act in a socially inappropriate fashion.
A situation that is more likely to result in aggressive behavior occurs when it is time to introduce a new horse, or reintroduce a former companion after an absence, to the group. It is preferable that horses become used to a new horse over the fence. It is also helpful to introduce the newcomer to a few of the animals in the middle of the current hierarchy first – neither the most dominant nor the most submissive – in order to smooth his passage into the herd.
If possible, it usually works best if domestic herds are composed of either all geldings or all mares. Many geldings retain enough sexual memory that they can become pests when mares are in season, and they may not only annoy the mare but get into fights with each other. It is extremely unusual for stallions to be turned out together, although some may tolerate a gelding as a companion. Stallions may also be turned out with mares, although there is a risk that an unwilling or feisty mare might injure too ardent a suitor. Mares with foals are likely to be more defensive with either geldings or a stallion present.
Aggression of Horses Towards People
Many of the behavioral problems between species occur because the two species signal their mood or intent in different ways. Horses are wonderful at picking up subtle nuances in our body language because that is how they communicate with each other. If we appear to be behaving submissively, they are liable to feel more confident and, in some cases, become more aggressive. If we appear too dominant, a self-assured horse may decide to display his position to us. If our posture doesn't change, the situation has the potential for leading to an aggressive standoff or escalation. Given that even the smallest pony far outweighs us, getting into a battle of brawn with a horse is never a good idea.
Much of what we perceive as aggression may just reflect a lack of education. Horses need to be trained from their earliest interactions with humans to respect our space and accept our leadership. This is particularly important with orphaned foals. While their bumping and jostling us, mouthing or even nipping, may seem cute when they are tiny, they will not be appropriate when the horse is older, and they will be much harder, or in some cases impossible, to eliminate. Kind, but firm, handling of foals is appropriate.
Certainly, getting a young foal used to being handled all over, accustomed to having his body manipulated and to strange sights and sounds at an early age, will make these experiences easier for him when he is older. He should remain relaxed and cooperative for these exercises. Any resistance on his part should not be bullied into submission but shaped gradually. Whether it is essential that these exercises are done immediately at birth or whether they can wait for the succeeding days has been much debated. Provided they are completed in a timely fashion and the mare is not disturbed by human intervention, performing this program immediately after birth appears neither to prevent the foal receiving sufficient colostrum nor the formation of an appropriate maternal bond.
With older horses, certain interactions with humans tend to be more likely to produce aggressive responses. Often these reflect a lack of preparation or warning to the horse so that it is taken by surprise. Things which often result in handler directed aggression include:
Girth tightening. This may be because the horse has been punched in the belly or skin and hair has been caught and pulled in the past. Fearing that their saddle might slip, most riders tend to err on the side of over rather than under tightening girths.
Entering the stall. The owner may be pinned against the wall, or the horse turns his hind quarters to face the owner as she enters.
Striking or yelling at the horse. Acting in a manner the horse perceives as aggressive or dominant and lead to aggression. Inappropriate handling of feet and legs and clipping can also cause a problem.
Syringe-use and other potentially painful procedures.
Approaching and cornering a horse at pasture.
Trying to coerce a horse to go somewhere – for example onto a trailer – he fears.
Leading a horse that has not learned to properly respect the handler, so he becomes distracted, shies, bolts or otherwise invades the handler's space – horses that are fine at home may become liabilities when taken to more exciting venues such as shows.
Horses may aggressively demand treats and bite and nip if they are not delivered promptly. The problem arises because the horse has been permitted to get away with this behavior, and even rewarded for it when the owner swiftly coughing up the treat to ward off an attack.
Other horses nip owners for attention. They cannot distinguish between biting on thick winter clothing and on bare summer arms, so this behavior should never be tolerated and allowed to become established.
In general, when designing a behavior modification program for human-directed aggression in horses, it is important to establish whether the behavior is motivated by fear or dominance.