Written by: Antonia J.Z. Henderson

A look at the science of fear in horses.

Thumbnail for Fear Factors: Why Horses Spook

Clix Photo

After a great lesson, you take your horse down the stable driveway for a relaxing cool out. You revel in the beauty of nature and of the magnificent horse you are privileged to have as a part of your life. Your reverie is abruptly disrupted when your horse flies sideways, nearly unseating you. You can feel his heart pumping wildly as you try to bring all of those four feet back to the ground and you wonder what on earth is so terrifying about a mailbox. The very same mailbox that has been at the end of this driveway, unchanged for the last five years.

The simple answer is that your horse’s mailbox hysteria is hard-wired. Horses are evolutionarily designed to be afraid, they are physiologically constructed for hyper vigilance and a speedy retreat, and their fear response is genuine – they really are afraid. And sometimes because we have inadvertently taught them to be so.

NATURE: THE HARD-WIRING

Since horses in their natural state experience high predatory pressure (i.e. they sit firmly on the “flight” end of the fight/flight continuum), they have been evolutionarily designed to experience fear and demonstrate it with a hair trigger flight response. Horses that were not worried about novel aspects of their environment were more likely to get eaten by predators and thus miss the opportunity to pass that nonchalant behaviour on to future generations. Although our modern sport and pleasure horses seldom face lion attacks, there are many sources of terror in our horses’ worlds. Your horse really has no way of knowing whether the mailbox could harm him or not, and when in doubt, the best strategy is to err on the side of caution.

Horses’ “flee first and ask questions later” default is also evident in how they perceive the world through their senses. Their laterally placed eyes give them an almost 360-degree perspective providing the advantage of detecting predators easily, but at the expense of visual clarity. And, designed for almost continual grazing, their vision is best when their heads are on the ground, putting them at a distinct visual disadvantage when under saddle. Their large, funnel shaped and upright ears that can tilt, turn and twist independently, are infinitely more adept at hearing sounds than our small, flat, immovable ones. However, their ability to localize brief, high-frequency, sounds, such as the snap of a branch or the snort of another horse, is limited. Their large olfactory bulbs with a huge number of receptor cells give them a highly sensitive sense of smell. Horses can detect sights, sounds and smells that far exceed our scope, making them well attuned to potential dangers; they are less skilled at pinpointing where and what those dangers might be.

Although spooky horses have been accused of being chicken-hearted, gutless or drama queens, it is unlikely that horses are inventing or embellishing the very real threat that they perceive. Researchers have demonstrated that fearful behaviours (e.g. snorting, avoidance etc.) are strongly correlated with physiological measures of fear (e.g. elevated heart rate, cortisol level, eye temperature etc.), suggesting that horses are not faking their fear to dodge their responsibilities. Horses that act afraid, undoubtedly are afraid (Dai et al., 2015; Leiner &
Fendt, 2011).

NURTURE: THE LEARNING

Flight in the face of potential danger can become habitual due to negative reinforcement where the removal of something unpleasant rewards the behaviour preceding it, increasing the likelihood that we will see that behaviour in the future. When your horse encounters a novel object, steps sideways or backward, or, worse, spins and exits, he lessens his anxiety by creating more distance between himself and the feared object, and is thus rewarded for this behaviour. Your horse soon learns that evasive behaviours get rid of scary things, and explosive behaviour gets rid of them even faster.

Perhaps the strongest predictor of fear reactions is when we sanitize (intentionally or not) the horse’s environment so that scary things seldom occur, and thus never provide an opportunity for the horse to habituate to novel experiences. A lack of exposure to scary things can leave our horses extraordinarily sensitive to what they perceive to be frightening. Show horses that are exposed to high activity stables, noisy machinery, whizzing golf carts, umbrellas, trailering, air travel and no end of constantly changing stimuli, become quite ho-hum about new and scary experiences because of this constant exposure.

Note that there is a concern that if we stroke, scratch and say reassuring sweet nothings to a panicky horse that we reward, through positive reinforcement, the very behaviour we would like to eliminate. However, research indicates that although attention may function as a reward for voluntary behaviours (such as patting a horse when he is stepping on you) it does not do so for involuntary behaviours such as generalized fear. Unlike voluntary behaviours, which gradually extinguish when they are no longer reinforced, involuntary behaviours such as fear persist while the threat is present and dissipate when the threat no longer exists (Foster, 2018).

However, we can use positive reinforcement to train more desirable behaviours, such as offering food to mark and reward relaxation in the face of scary things.

THE UP SIDE

Leiner and Fendt demonstrated that fear responses (physiological and behavioural) can be eliminated with habituation and desensitization training (gradual and incremental exposure to the feared object). Adding a food reward to mark the relaxed behaviour we are after appears to be even more effective (Sankey, 2010). It is clearly in our best interests to train our horses preemptively to tolerate more and more novel objects and situations.

And lastly, the fact that horses work for us with that flight response always on the back burner is also a critical component of what makes horses horses. That edge is a part of what makes barrel racers fast, and jumpers careful, and dressage horse’s passage and piaffe harder and higher. And it is also what makes equestrian sport so stupendous, because we who work with horses know how hard they try, how far they stretch and how much of a leap of faith that it takes for a good horse to do the impossible things we ask of them every single day.

Although a spooky horse tries our patience, and our safety, it is worth remembering that spooking at the mailbox is, in fact, a normal behaviour. Running around barrels at break neck speed, jumping enormous obstacles that would be much easier to go around and dancing to music in front of giant jumbotrons is not.