Why Do Horses Rear?

As seen in the June 2019 issue of Horse Deals.

Most people would realise what rearing is,” begins Dr McLean, “but for the record, it is when the horse stands on his hind legs and throws his forehand upwards. This ranges from front legs just off the ground to the horse being fully vertical. I have ridden a lot of rearers, in fact, that was the most common problem I dealt with when I travelled the country riding horses in every state, three or four times a year. I never had one come over on top of me and what makes them do that is if the rider holds on to the reins and the horse overbalances. Leaving the reins alone is really a major safety aspect when and if riding a rearer.

“Rearing is part of the suite of behaviours known as flight responses that include bucking, bolting and shying. To drill down even further, it is a conflict behaviour, and what that means is that it is about conflicting motivations. So when animals are motivated in two opposite directions, which can occur in hand as well as in the saddle, where the rider urges the horse forward and it doesn’t want to go where it is being pointed. They can start by doing jumps to the side which can escalate into rearing and some horses can learn that behaviour. Also, it can occur when the rider is hanging on to the reins and the horse perceives the stop button is on whilst being urged forward by the rider’s legs at the same time (clashing aids), so the horse has nowhere to go but up.

“The origins of this sort of behaviour are quite interesting. The ancestors of the modern horse are from Eurasia and there are four ancestors, basically the short and tall cold temperature adapted horses and the short and tall hot temperature adapted horses. The predators of the horse in the largely cold areas are mainly wolves, and it does not make any sense to run away from a wolf. The speciality of the dog breeds when hunting is to run and chase and they never give up. Dogs can outrun their prey by just being consistent. It therefore makes more sense for the prey, the horse in this case, to stand its ground to strike and rear. So rearers tend to come from the cold-adapted ancestors. However, the buckers and bolters tend to come from hot adapted ancestors, because their predators are largely big cats. Cats can run fast but not far and they tend to jump on the back of their prey. The origin of bucking, to get rid of them and to escape by running away.

“Almost all domestic horses have a mixture of the cold and hot adapted, so you can get both a rearer and a bucker. However, frequently there is one predominant adaption. That is why we tend to see some breeds that are more inclined to rear, like Warmbloods, because they have more cold adapted genes, whereas Thoroughbreds with more hot adapted genes are more likely to buck and bolt. (There are of course exceptions to this rule, with rearing Thoroughbreds and bucking Warmbloods, however a lot depends on the present cause of this behaviour).

“We often see young horses rearing as they play in the paddock, but that is actually practice for manoeuvres that they will need as adults in their wild life, and it is to be hoped not domestic life. People often think that play is them just having fun, but that is an incorrect view of it. It is enjoyable for them because otherwise they would not have the motivation to practice it. Nonetheless, it is all about life’s manoeuvres. Predators play by chasing, prey animals play by running away. Colts especially play by biting one another’s legs, to bring it down, then getting up in the air and straddling the other horse and that sort of thing. It is playing, but it is also about serious life and death lessons. It can also pose a problem for the rider, if the horse typically practices this behaviour in the paddock.

“In terms of dealing with rearing as a rider problem, the most important thing is to establish the basics of the horse’s education and to keep them well oiled. Testing the horse in daily training and warm ups that the horse goes from light aids and slows from light aids, and that the two are clearly distinct and certainly separate in their aiding systems. It is really critical that the basics are tested. It is very important to practice transitions; up and down gaits and within the gaits, as they are the essence of every single response and movement that needs to be practiced and well oiled, so that the horse does all his lateral work and all his transitions very well. And it is critical that the rein aids don’t compromise the going forward aids.

“Horses learn the rearing habit and in some it is an innate response and some will never rear. They learn to rear by negative reinforcement. When the horse goes up, he experiences a looser rein and the leg slides off the control panel on his rib cage. In this case the bad behaviour is rewarded. People have to realise that if the horse goes up, you have to loosen the reins. That is why riders, if they are skilled at riding horses that rear, will keep kicking them forward or turning them sideways with the rein, so that is it not actually a release of pressure.

“It is interesting too that most horses when they go up, land to the left and most shying is to the left too. This is because of the biomechanical difference between the diagonal pairs (near fore/off hind etc.) One diagonal pair tends to be much more powerful and thrust forward, and the other is more powerful at reverse thrust. That difference is important in all quadrupeds, as it gives them a pre-programmed way of swerving away from predators. That is how buck jump riders and bull riders get to know patterns of horses that they ride, because the horses just don’t randomly buck. They follow a pattern they have learned as a defence mechanism against predators. The right foreleg seems to be the leg that swings outwards and most horses tend to be heavier on the right rein. Most horses fall out right rather than left, and the right front leg is more dominant and they tend to push left. A rear often evolves from a turn left, which becomes a leap left and finally becomes a rear and is reinforced now in a brand new way by the amount of time he spends in the air.

“Horses are very quick to learn by trial and error, so they easily learn what they can do in an arena. They are fine in the warm up, but once in a dressage or jumping arena, their behaviour can change. Riders don’t help sometimes because they become nervous and tense when they enter the ring. That can alarm the horse and trigger a whole lot of unwanted behaviour. That is why it is important to get practice in arenas when they are not riding for ‘sheep stations.’ It is important also that riders get lessons in correct technique and position. It is essential as it will help both to avoid problems and fix problems. If you train really well and you don’t confuse your horse and you have a good riding technique, then you are significantly less likely to cause or encounter problems like rearing.

“The tendency of the horse to trial the correct response is very much determined by genetics and also his early life experience. If you touch a young foal on the rump during his first interactions with humans and he kicks his bottom up in the air and runs off, you have taught him one very bad lesson and that is the first step towards him becoming a rogue. You really have to arrange your early interactions with horses well. If every horse came with an excel spreadsheet of every interaction with humans and his genetic tendencies, we would easily see the origins of bad behaviour.”

Written by Anna Sharpley.

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