Health

Point of View: Understanding How Horses See the World

There can be more than meets the eye when it comes to behavioural issues. Get better results when you adapt your training to how horses see the world.

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By: Angie Beaudet |

As humans, we have a tendency to expect our horses to see what we see, forgetting that their vision differs considerably from ours. By understanding equine vision and taking into account the way they perceive the world, we can learn to tailor the way we train our horses in order to allow them to become more confident and relaxed in their environment.

1. Horses see colours differently than we do. Humans have trichromatic vision (sensitive to the three primary hues of red, green and blue) whereas horses have dichromatic vision (only distinguishing two colours). They cannot see reds as we do, but rather see the world entirely in shades of blues, greens and greys. This distinction is particularly important in disciplines such as show jumping, where being able to identify rails is of great importance. Having alternating contrasting colours on jump poles is meant to help horses better distinguish them from the rest of the environment. Studies confirm that rails that are one solid colour are more often knocked down than if they are two or more contrasting colours

TIP: It is important to make sure jump rails are easily visible in order to build confidence during training sessions, especially with young or green horses.

2. Horses have better night vision than humans. Horses have one of the largest eyes of any land mammal, along with a large pupil designed to allow generous amounts of light to enter. They also have more rods (photoreceptor cells in the retina responsible for vision in low light) than humans, with a higher proportion of rods to cones (active at higher light levels). Another interesting adaptation is that horses have a tapetum lucidum, a common characteristic shared by nocturnal species. Positioned directly behind the retina, the tapetum lucidum acts as a retroreflector, sending visible light back through the retina and allowing horses to have superior vision on cloudy days and in low-light conditions.

TIP: Low-light conditions may not be ideal for practicing jumping or galloping cross-country since your vision will be poor, but training in a safe environment or taking your horse out for a relaxing moonlit trail ride can be the perfect opportunity to reverse roles and allow the horse to be your eyes. Work on your ability to trust your horse, allowing him to think and giving him some freedom to make decisions.

3. Horses’ eyes take longer to adjust to changing light conditions. Although horses can see better than humans in the dark, the change from bright light to a dark environment takes the equine eye more time to adapt than the human eye. Entering a dark horse trailer or simply going into an unlit barn on a sunny day will leave the horse blinded for a long period of time.

TIP: Take it slowly when going from light to dark (or the reverse) environments and reassure the horse with your voice or hand while his vision adjusts to the change in light.

4. Horses have 350-degree vision. A horse’s eyes being located on the sides of its head gives it about 285º of monocular vision (seeing with one eye at a time) with a small 65º section of binocular vision in front. This allows them to see nearly all the way around; however, there are two “blind spots”: one in front of the face and another directly behind the head extending over the back and beyond the tail. This means that as a horse jumps an obstacle, it disappears from view at the point of take-off.

This vast range of sight also means that horses have huge amounts of info to process. Their ability to see potential danger far exceeds ours and, programmed as prey animals to be on high alert, it isn’t that surprising that horses spook so easily. Carriage horses become much more focused and relaxed with blinders on because they don’t have the overload of visual information to process.

TIP: Working in collection where the horse’s forehead is perpendicular to the ground will further limit the horse’s sight. Rather than trying to restrain a horse in this frame for the entire session, try short periods on the bit alternating with relaxation so that the horse has a chance to stretch out and look around and collection will not become a source of stress.

5. A horse’s eyesight may not be as good as a human’s. Perfect vision in humans is 20/20, but what about horses? Studies have suggested that visual acuity in horses may lean more towards 20/30 vision (meaning means they see at 20 feet what a person with normal vision sees at 30 feet). This would mean that our vision is 50% better than theirs – except in low light, where their vision exceeds ours. Things we can distinguish clearly at 20 feet could actually appear slightly blurry to horses.

About one-third of horses can also be near-sighted or far-sighted, making some individuals better suited for certain disciplines that rely more on good vision close up or good vision at a distance.

TIP: A near-sighted horse may not be able to distinguish a jump clearly until he is much closer to it, while a far-sighted horse may be better able to judge the distance to an obstacle from far away, but as he closes in, the rails may appear blurry. The former may be better suited to a slower-speed sport such as dressage or hunter courses, while if a far-sighted jumper is regularly knocking down rails, a retinoscopy may be able to determine the extent of its vision issues.

6. Horses have excellent motion detection. Having evolved as prey animals, the horse’s eye is designed to detect minute movements that could hide a potential threat or predator. The human eye is not as developed for this type of high-precision movement detection, so not only does the horse have a much larger visual field with more info to process, but they can also actually pick up on tiny movements we may have missed.

TIP: Desensitization to movement is an essential part of training. If you only ride alone in a quiet environment, your horse will never become less spooky. Take advantage of riding or lungeing when there’s a lot of activity at the barn: people walking around, other horses being ridden, tractors driving by, etc. Eventually, your horse will become accustomed to all the movement and react less intensely when something new pops up.

7. Head position affects vision. When horses are viewing a novel object, it’s quite common to see them either raise their head, lower their head, or even tilt their head to the side. The reason for this is that the equine retina contains a linear area with a high number of ganglion cells, allowing them to see with more clarity when looking through this part of the retina. Researchers have found that horses see everything at eye level with the most clarity; anything positioned higher or lower is more difficult for them to distinguish clearly unless they move their heads.

TIP: Allow the horse to position itself to better view the object. If the horse is very tense, back off to a distance where the horse is comfortable and approach it slowly by working in circles (placing the object in the horse’s monocular vision rather than head-on).

Armed with these facts about a horse’s sense of sight, it’s up to us to train in a way that takes into consideration how our horses see the world around them, thus helping them achieve a more calm and attentive state of mind.