Understanding Our Horses’ Five Senses

“Horse welfare is absolutely our most critical issue right now,” said Jones. “It is not just what organizations like USEF and the FEI can do, but about what everyone who works with horses can do on a regular basis to make a big difference in their own horse’s life.”

Jones, who taught the neuroscience of human perception, language, memory, and thought to college students for two decades, has combined her scientific knowledge with her passion for horses by developing brain-based horsemanship.

“We have put horses to use for our benefit and not theirs for at least 4,000 years. They have helped us build monuments, fight wars, carry heavy burdens, and travel the world,” she said.

“We have had very high expectations of them — and we still do. Historically, however, we have not given them the respect or the scientific attention that they deserve.”

We sometimes assume that animal minds are simply weaker versions of human minds, but the more we respect how their minds work and recognize they are simply different — not inferior — the better we can communicate with them.

Sight

“One third of the human brain is devoted just to vision,” Jones explained. “We always think the senses that are strongest in humans are equally strong in other animals and vice versa, but they really aren’t. There’s this myth that horses have this fabulous sense of vision and that they negotiate around their worlds by using vision, simply because that is what we do.”

When it comes to horses’ vision, many of us know that they have a much greater horizontal field of vision than humans do, but we don’t often realize that they have a much smaller vertical field of vision.

“Horses have a huge panoramic band of vision without ever having to move their eyes ... but we see far more of the visual field above and below our gaze than a horse can,” according to Jones. That means that a horse may get scared by a bird that flies into their field of vision, even though we had been able to see the bird all along.

In addition, a horse’s depth perception is 72 times worse than a human’s. That means we have to reconsider our expectation that a horse can find a jumping distance better than we can, or identify the exact location of a barrel that can’t be knocked over.

It takes 45 minutes for their eyes to adapt to darkness, compared to 25 minutes for people. That means if you lead a horse into a shaded barn from outdoors, they can’t see the inside of it nearly as well as we can. Similarly, if you warm up your horse outside in the sun and then take them into an indoor arena for a jumping class, they can’t adapt as quickly as humans.

“Expecting the horse to immediately begin the course 15 seconds after walking into a dim arena sets them up for failure,” said Jones. “Instead, we need to set our horses up for suc-cess and do everything we can to try to help them achieve it.”

Because a horse has a prey animal’s brain that is designed to be vigilant and on the lookout for danger, it makes them anxious and ner¬vous if they are put in a situation with reduced sensory ability.

Identifying different colors is another way our brains are dramatically different to equines.

“Horses see about 10,000 faded colors, while humans see 2.3 million colors. Horses also can’t distinguish between red and green,” said Jones. This needs to be taken into account when designing jumping courses or any other situa¬tion where they may struggle to differentiate certain colors from the background.

In addition, “their ability to see detail is worse than ours and they can’t see well close up, but their ability to detect tiny high-speed motions is excellent and much sharper than ours,” she continued. “Horses and humans looking at the same view do not see the same things. Their whole world looks vastly different from ours.”

Smell

“It’s really remarkable how little attention is paid to the sense of smell in horses,” said Jones, explaining that they have the neuro­logical machinery to smell odors as well as bloodhounds do. “Horses use their noses to navigate around the world.”

Few people use the sense of smell to help train their horse or build trust with them, she said. “Horses might want to tell us, ‘Hey there. Forget about your eyes for just a second and think about your nose instead.’ It makes a big difference.”

Horses are prey animals whose brains are driven by fear, and that sense of danger can be communicated through unfamiliar smells. When introducing a horse to a new barn, Jones recom­mends allaying fears by allowing them to sniff the environment on a long lead rope for an extended period of time — up to an hour if need be.

In addition, when approaching a horse for the first time, let them really sniff you. “They can get so much information out of your clothes, the food that you just ate, whether you smoke, what you drink,” Jones said. “Horses can smell the hormones that are released dur­ing times of fear, both human hormones and equine hormones.”

That means that horses can also smell the fear of their barn mates. “If a vet, farrier, or trainer works with one horse who is frightened and then immediately walks over and grabs the next horse, they’re transferring fear,” Jones explained. She recommends a change of shirt, a new location in the barn, or hand washing to reduce the smell of fear and make the next horse feel more comfortable.

Hearing

The three main perceptual aspects of hear­ing are pitch, loudness, and sound localization. The softest sound a human ear can hear is 0 decibels (dB), while a horse can’t hear lower than 7 dB.

“We don’t have to speak louder to our horses than to each other, but if we speak more quietly, they cannot hear us,” Jones explained. “Many people whisper to their horses, not realizing that if another person standing in the arena cannot hear a verbal command, the horse probably can’t hear it either.”

Horses can hear low and high pitches from 55 to 33,500 Hertz (Hz), and people can hear 20 to 20,000 Hz. Because equine ears surpass ours at the high end of the spectrum, they can detect ultrasonic sounds like a bat or a silent dog whistle. “One of the reasons that horses dislike ear trimming, for example, is because they can hear ultrasonic frequencies like clicks and whis­tles from the clippers, especially when pressed up against their ears,” said Jones. “Meanwhile, we have no idea those sounds occur.”

Horses are calmed by music without sud­den changes in tempo, so they prefer Mozart to Beethoven, soft rock to techno, and country music to heavy metal, Jones wrote in “Horse Brain, Human Brain.” The right type of music can also have a calming effect on them. A study of Arabian racehorses found that horses who lived in a barn where harmonious background music was played had lower heartrates over time and won more races.

While the size, shape, and position of horses’ ears may make us assume they are better at sound localization (identifying where a noise is coming from), in fact, humans can identify a sound within one degree of precision, whereas a horse’s precision range is only 22 to 30 degrees.

Taste

Approximately 80% of the sense of taste for both horses and humans comes from smell (this may resonate with people who temporarily lost their sense of smell during the COVID-19 pandemic). Horses will use the taste buds on their huge tongues (which weighs 2.5 pounds, on average) to translate molecules into neural impulses to the brain. Pleasant sensations are transmitted when sweet or salty foods are consumed, as sugar and sodium are needed for brain function.

Horses are more tolerant of bitter tastes than humans, especially when items are chilled, which is why they are more apt to consume bitter medication that is kept in a fridge.

However, Jones states that horses are not adept to identifying poisonous plants or stagnant water by taste, which is why it is our responsibility to make their environment safe by removing dangerous vegetation and ensuring a fresh water supply. When traveling, horses can often be encouraged to drink more by adding sweetener, peppermint, apple essence, or beet pulp water to their buckets.

Touch

Equine sensitivity to touch is better than that of human fingertips. This is very important to understand in regard to horse welfare — such as when using whips and spurs — as it means they are extremely sensitive.

“A horse can sense five dandelion seeds of pressure on their skin, and no human can do that,” Jones said. “I think we need to recognize that horses can learn the meaning of very light, sensitive aids. If they have learned the meanings properly, they will not need spurs, whips, and rough or strong handling. What horses need from us is more lightness and sensitivity, not more strength.”

Horses feel even the lightest aids, she continued. If they don’t respond, it’s either because they don’t know what the aid means, or they have been taught that it’s OK to ignore it.

“Making the cue stronger doesn’t help with their confusion about what it means or with their ability to ignore it,” Jones said.

“We will never overcome the differences between horse and human brains completely — they are much too vast,” she concluded. “But we can improve our connection by gathering knowledge in two ways. First, in a scientific sense, by funding and conducting more equine cognition research. Second, in an individual way that we can all do during our daily work in the barn, arena, or on a trail. Human brains operate on the basis of assumptions — we cannot eliminate them, but we can change some of them. So, I encourage riders to learn more about their horses’ brains and create better assumptions, such assuming that your horse is trying his best 99% of the time … because he probably is.”

Photos: Leslie Potter/US Equestrian, Isabelle Whiteside/US Equestrian, Avery Wallace/US Equestrian