We often write about the politics wild horses are caught in yet rarely about the wild horse itself. We are busy on so many fronts from range, reports, conversations and litigation. Volunteer Cathy Ceci prepared this piece on the vision of a wild horse. We hope you enjoy!
Laura Leigh has been asked multiple times why she loves horses so much. In a recent interview she responded, “Horses have the largest eye of all land mammals. They say eyes are the mirror of the soul. Perhaps in that eye we see ourselves reflected back. Maybe that is why so many people love or hate them. Maybe it has more to do with our own paths to redemption or damnation? Walking a path of self betterment or self loathing?”
Recently, I was out on the range with Laura Leigh, observing and documenting wild horse numbers, their health and range conditions. We are able to clearly watch their natural and instinctive behavior at work, and being constantly on guard, these behaviors are much more evident than those of domesticated horses.
With their acutely attuned senses, wild horses are very alert to our presence, many times before we see them. Their fine eyesight and keen hearing are vital to picking up any unusual sights and sounds quickly, allowing them to identify dangers at a distance and escape to safety. Using sight and sound with other senses is crucial to their survival and wild horses use all of their senses in many different combinations.
How do they see me?
A horse’s eyesight is their chief means of identifying threats, as well as food, water, shelter and other herd members. Their eyes are the largest of any land mammal and they see mostly with monocular (one-eyed) vision, viewing over 200 degrees on each side. Threats come from all sides. They see much better where that monocular vision overlaps, becoming (two-eyed) binocular vision, up to 65 degrees, directly in front of their head. Simply moving their head from side to side and up and down allows those blind spots to quickly come into monocular view all around them. Their ability to detect and focus quickly on the slightest movement, thereby identifying threats, is key to their survival.
Depth perception is similar to humans but they must use binocular vision (in front of their head) to determine that depth, or how far out or how deep an object is. When only one eye sees an object (monocular vision), which is the norm, it’s difficult to determine exactly how close or distant that object is, especially if that object is moving quickly or may be a muted color.
Their color vision is less than humans, most horses seeing in shades of gray. Almost all horses can clearly distinguish shades of blue and red, while only some can see greens and yellows. However, in most tested horses, yellows and green tones look very similar to grays. It also takes longer time for their vision to adjust from light to darkness. Think of going into dark shadows or an unfamiliar barn or trailer. It looks scary and their eyes don’t adjust quickly, even coming back into the light. Their night vision, however, is very good, better than humans.
Their eyes are capable of distinguishing detail and patterns, both close up and at a distance. While they can focus faster than humans, they don’t see quite as clearly as humans at a distance. This means that at the same distance, humans can see something clearly and identify it faster than they can. So for wild horses, foraging in the wild is a matter of searching among muted, even grayish visual patterns, and relying heavily on their acute sense of smell and established grazing patterns and water sources. For a wild horse, unfamiliar shapes, especially at a distance, strange sounds and unusual smells are all perceived as threats. When viewed with one eye, (monocular vision) first, they tend to turn toward things to better see with binocular vision and use other senses to identify whether a threat or not.
You may have heard the myth that equines must “see” an object with both eyes for it to imprint on both sides of the brain. Recent studies have dispelled this belief. Instead, it is more likely that they don’t always “recognize” the same object viewed from a different angle, even with the same eye.
An interesting observation is that the left eye in horses is known to be the ‘rapid reaction’ eye, having a much stronger and faster flight reaction when presented with frightening stimuli on the left side. The left eye is generally preferred for overall viewing, but even more so when a human is involved, even when the human is well known to the horse.
These are all things to keep in mind when we try to see the world through a horse’s eyes. Maybe if we start trying to understand their world a bit better, we can figure more ways to work with them, in ways less traumatic, with much better results.
How Your Horse Sees, Dr. Sharon Spier, U.C.Davis, California
Horse Vision, by Deborah Johnson
The Thinking Horse: Cognition and Perception Reviewed
Visual laterality in the domestic horse (Equus caballus) interacting with humanshttp://www.ncbi.nlm.nih.gov/pubmed/19618222?ordinalpos=5&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
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Categories: Wild Horse Education
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