Tag Archives: equine vision

Let’s Talk about Equine Peepers, shall we?…






I was interested in this topic after going outside last night in the dark.

Do you ever go outside at night because you think (for the hundredth time) that you left the water on?  Or, you hear something go “bump” and you are sure it is a loose horse?  Or, my personal favorite, you KNOW a horse is loose and running amuck…  Me, too.  And, what always amazes me is that all the horses are awake at whatever hour and their eyes are beaming at me.

How do their eyes shine at night like that?  And, how do they run amuck in the dark and never run into anything?  How can they see so well with fly masks on at night (not that I recommend this but it has happened around here…)?  How well do horses see?

FIELD OF VISION?

Let’s start with the field of vision.  Now you all probably already know that a horse can see, while standing, much more than we can because of the placement of their eyes on the sides of their heads (vs. ours which are placed in front).  Since the horse is a prey animal, these wide set eyes allow him to see almost 360 degrees.

BLIND SPOTS

However, he does have blind spots.  They are directly in front of his nose, the spot below the eyes and directly behind his behind.

Now, what people sometimes don’t understand is that when we approach from the front of a horse, there comes a point where we disappear.  Imagine how upsetting that would be, eh?  This is why a horse suddenly jerks his head up or sideways as we get close to his face.  So, don’t do that.  Don’t approach straight onto a horse.  Come from the side.  It makes the whole thing easier.

Same with the rear.  You’ve heard not to approach a horse from behind.  The reason is that he cannot see you if you come up directly on his tail.  This is why you might get kicked.  And, this is why I so admire the trick riders who can run up and mount from behind.  Obviously, the horse really trusts his rider.

MONOCULAR VS BINOCULAR

This is another interesting concept.  Since their eyes are on the sides of their heads, they can see all around them while their heads are down, grazing.  When their heads are down, both of their eyes cannot focus on anything together because they are seeing completely different things.  Do you see what I mean?  So, if their heads are down, the right eye is seeing what is on the right and the left eye is seeing what is on the left — monocular.

Now, the interesting thing is that if a horse senses something moving while his head is down, he NEEDS to raise his head to see it dimensionally.  In other words, when he is alerted, he naturally raises his head so that he can focus on the object with both eyes or BINOCULAR vision.  So, that is why he “spooks” except it isn’t spooking at all.  He is just checking it out.  And, it takes a few moments for his eyes to work together so he kinda bobs his head until it all makes sense to him.

Another reason horses move their heads up and down when they are trying to figure something out visually is that their field of vision is narrow.   Objects seen the clearest are the ones that fall within a narrow area–the horse tilts his head in order to get as much of an object as possible to that area of his eye.  Basically, all that sudden head movement is really only to help him focus, visually, on the object.

If we understood this monocular vs binocular vision a bit better with our horses, we would have less fear around the rapid head jerk that they do when they see something they cannot identify immediately.  It is only their eyes adjusting to better qualify what has moved in their line of sight.

MOVEMENT

Since the horse is a prey animal, when they see movement, they need to check it out — unless that movement is accompanied by a sound they recognize or if they already understand what created the movement.

So, if the head is down, they will raise their head to use their binocular vision.  And, if the head is already up, they will look directly at the movement and prick their ears.  If they cannot distinguish the movement, they will look to you.  If they are not confident in your leadership, they will fret.  And, if the movement smells bad, they will run.

Movement is a big deal to a prey animal.  The more hours training and desensitizing, the wiser the rider and the mount.

THE ALMIGHTY WIND

Well, dontja just hate riding in the wind?  I especially hate it with a green horse.  In fact, I try to avoid it.

Do you know why they spook in the wind?  Too many things are moving, darn it!  How can a poor horse watch it all when so many things are moving?!  The entire herd gets all whooped up, except the oldies, because they know better.

In my humble opinion, if you have to ride in the wind, take your seasoned mount and sing a lot!

PUDDLES

I know we have been told that horses don’t have depth perception.  This isn’t true.  Theirs is as good as ours.  But, if a puddle is murky, they cannot see the bottom and that is a problem.  Otherwise, maybe they don’t want to get wet or walk on wet rocks.  That myth that they cannot distinguish depth has been maligned scientifically.  When trained to prefer a photo with depth, a horse can pick out the deep images.  For example, if  a trained horses is shown a photo of train tracks going off to infinity or a park bench, he will pick the train tracks every time.  Or, anything else with depth.

NIGHT VISION

“What there is of it is based on anatomical and physiological factors, not behavioral. What we do know is that the equine retina has many more rod receptors than cones, about 9:1. These receptors are responsible for vision in dim light. The eye also contains a tapetum lucidum (the reason eyes of nocturnal animals shine in the dark), which reflects light and enhances the light-gathering properties of the rods. All this indicates good night vision but there may be a hitch. The tapetum lucidum, while increasing sensitivity to dim light, may also, because of light scattering, reduce visual discrimination. Nonetheless, horses are active during the night, grazing, moving about, avoiding obstacles. This gives us a behavioral clue that their scotopic vision is decent.”  by Evelyn B. Hanggi, M.S., Ph.D. I copied that because she said it so well…

Yes, they can see better than us at night.  And yes, that is their actual eyeball that you are seeing reflecting back at you when you are walking around in your nightie to turn off the water…

And, yes, Paul Revere totally relied on his horse.

HEAD SET AND EQUINE VISION

I don’t know about you, but I hadn’t really thought about this… Horses with a dressage type head set cannot see in front of them.  They can see the ground and a few feet beyond, maybe, but they really are depending upon the rider to let them know if they are OK.  So, this may explain why horses are not willing to set their heads without a lot of trust and time.  Also, it tells you why they never hold their heads absolutely vertical when they are on the trail.  They can’t see!

I read about a few crashes in dressage arenas where a few riders were practicing diligently.  However, you gotta wonder what in the heck the riders were doing, eh?  Even if the horse is keeping his head exactly vertical, the rider is supposed to be looking where he is going!  I find this hard to believe but I did see documented cases which were recorded to prove that horses in a vertical headset have marred vision.

RIGHT SIDE VERSUS LEFT

We all have been trained to show the horse whatever you are showing him, on both sides.  Sometimes people say that horses cannot learn something on both sides of their heads at the same time.  Well, that isn’t true.  A horse can “think it through” and understand that whatever happened on the right can happen on the left.

What takes them time, and why you might want to show them things on both sides, is that they cannot turn objects well in their minds – quickly.  For example, if you showed them an odd shaped brush on the right side and then turned it upside down and backward on the left side, they might not recognize it at first.  But, if you showed it to them the same way on both sides, they usually will understand after a few seconds.

Another example is a mailbox or a boulder.   Most horses think these items will eat horses, even if they saw it going down the trail and now we are just going back.  The difference is in the image itself.  Is the thing exactly the same from all angles?  Probably not.  Since horses cannot flip objects or rotate objects in their brains as fast as we can, it takes them a while to recognize the same object from a different angle.  Your patience really helps here.

20/20?

Actually, horses see a bit better than we do.  We are all familiar with the 20/20 thing in humans.  Well, a horse sees 20/30.   A dog sees 20/50, a cat 20/75 and rats see 20/300.   Holy cannoli!

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HORSE AND MAN is a blog in growth... if you like this, please pass it around!