Understanding The Horse's Senses By J. Foley
In Today's Post I'll talk about "sight". One often hears remarks on a particular horse's beautiful or expressive eyes. Horses have the largest eyes of any land mammal, and their eyes convey different states of mind such as trust, uncertainty or fear. In common with most animals that are preyed upon, the horse's eyes are positioned on each side of its head, not the front, affording it a very wide field of vision. With a hugh field of peripheral vision available to it, the horse has only two 'blind spots'; one directly behind it and the other around six feet directly in front of or beneath its nose, where vision is out of focus, at the least. If you walk towards a horse; there comes a point where it can't focus on you, so it will turn its head away or back up until it can see you again. For example, when going to catch a horse from the field, the reaction described above could be interpreted as the horse not wanting to be caught, when in fact, if you approach from the side and the horse can keep you in sight, it will stand happily for you to reach it. If you stand behind a horse it will generally turn its whole body or head and neck to get a constant view, but a young or nervous horse can easily react with a warning kick to an intrusion it can't see.
Because of the particular position of its eyes, the horse needs to use its head and neck when reacting to visual stimuli. With the head held high it can't see the ground in front of it. If you watch a horse pick his way across rough ground, it will lower its head almost to the surface it is traversing.
A strange or unfamiliar object on the ground or in a hedge to its side, for example, will have the horse tilting its head to the side for a closer examination. If its 'alien' the horse will pass the oject with this sideways tilt of the head and a sideways step of the body. This forms the basis of 'shying' and in training it is important that the rider understands this impulse, and gives the young horse a chance to look at the object. If the reaction is punished, either by design or mistake when the rider becomes unbalanced and pulls on the reins, the horse rapidly learns to avoid such hazards in the future, which can be the foundation of a real problem.
It was once thought that horses were color blind, but evidence suggests the opposite-although horses seem to recognize yellows, greens and blues more easily than reds, purples and shades of gray.
Horses also have excellent long range vision(picture a horse in the field gazing at something the human eye can't see)and good night vision.
horseback riding by J. Foley