Prepare for Takeoff! - Equine Vision (Part 2)

An equestrian grand prix show-jumping class takes place over a course of 10 to 16 obstacles that reach heights and spreads of up to 6'6". It's a thrilling event to watch! Horse and rider try to beat the clock while leaving all of the rails up. So how does the rider get the horse to jump something that's taller than them both? Is it training, enjoyment, perception, or a combination of these elements?

Part 1 of this series on equine vision examined the difference between monocular vision (using one eye to scan a broad area of the visual field) and binocular vision (using both eyes to look ahead and perceive depth). The horse uses both techniques: one for protection and one for speed. Although the equine is an animal with a broad range of vision (350 degrees), it has two blind spots – one directly behind it and the other just in front of its nose to beneath it.

Binocular Vision Impairment

Without getting too technical from an equestrian's standpoint (I've spent many hours in the saddle during the past 19 years), there are certain things a rider asks a horse to do before jumping is even considered. One of those things is for the horse to go "on the bit", also known as "in a frame". A simple visual is to picture a vertical line running through the horse's ears, forehead, and nose - straight to the ground. This head position usually indicates that the horse is accepting the rider's aids (signals) and is fully engaging the muscles in its body.

This head position is not conducive to binocular vision, however. Think about when you use a pair of binoculars. You point your nose straight toward what you want to look at, right? Well, in this case, the rider is asking the horse to point its nose toward the ground. If you did that with binoculars, all you'd see is dirt! But when the horse pokes its nose straight out in jumping, it's considered a big no-no (even though it might want to do that to look at something that seems scary).

So how does the horse see the big jump that's coming up – let alone know when to take off (relative to how big it is) and how long to stay in the air (relative to how wide it is)? Those are a lot of questions to figure out when you're traveling roughly 12 to 20 miles per hour and can't even look straight ahead at where you're going.

How a Horse Negotiates a Jump

For a horse, these are the steps to negotiating a jump:

1. Gauge relative distance by making size comparisons (40 feet away)
2. Note distance remaining; adjust stride accordingly - if horse doesn't, rider needs to (24 to 36 feet away)
3. Prepare for takeoff, and…
• Judge width by viewing distance to back rail (12 feet away)
• Take off about as far from the base of the jump as it is tall (if it's 4' tall, take off 4' away)
4. Get ready for the next jump in the air – either begin to turn toward the next one, or land (hopefully clear) and head to the next jump

While a horse can jump without a rider (an exercise called "free jumping"), it's got to be a team effort during competition. Sometimes, the rider saves the horse from a bad spot and vice versa. Why do horses "refuse" jumps? It could be that they don't "see" the distance to the jump. Other times, the rider hesitates and the horse thinks, "If you don't feel sure about it, then I don't either!"

Resources:

http://en.wikipedia.org/wiki/Grand_Prix_show_jumping

http://www.equisearch.com/horses_care/health/anatomy/eyes_091003/

http://bowlingsite.mcf.com/movement/hjump.html