06/18/2003 12:00AM

Running scared under the lights


INGLEWOOD, Calif. - It's time again for Friday night at the races. Everybody duck.

During the current Hollywood Park meet, which conducts night racing once a week, there have been at least three scary incidents of horses gone wild in the outdoor saddling paddock, as twilight fades and darkness begins to fall.

Sadly, there was one fatality. In another case, a filly flipped and fractured her withers. Then there was the horse who spooked, reared, and got his legs tangled in a low limb of a tree. According to eyewitnesses, this was akin to watching a terrified pig being pushed off a roof and encouraged to fly.

A weekly night racing program might add a few customers - at least, that's what we have been told - but it also adds another layer of potential danger to an already dangerous endeavor. These are not Labrador retrievers being led around on a dangling leash. A Thoroughbred, on his best day, is still just a little bit prehistoric.

There are racetracks that present only nighttime racing. This, at least, gives the local supply of horses a chance to come to terms with the alien environment. In Southern California, however, a horse might find himself confronted with the shock of night racing only once or twice in a year. As a result, this rare exposure can play havoc with both ingrained behaviors and the physical senses.

Thoroughbreds are not trained at night. In fact, they are rarely let out of their stalls after dark. They grow accustomed to illumination by natural daylight. Nighttime, for a horse, is the time of the predators - the wolves, the cougars, and the other creatures who lie in wait for a shot at a juicy horse filet.

"Day or night, vision depends upon light, and nothing can alter the fact that there is not much light around at night," writes Stephen Budiansky in "The Nature of Horses."

The horse sees better than humans at night, Budiansky continues, but it does so at the price of considerable loss in acuity. Acuity, in this case, simply means the ability to interpret what the eyes are gathering.

"The mechanics of the horse's eye creates an optical image very different from the one produced by the human eye," Budiansky writes. "And the horse's brain uses that image to construct a picture of the world even further removed from our own. Because of the paramount importance of the brain in defining visual perception, we can never truly see the world through a horse's eyes."

This should be obvious. Sitting here at the top of the food chain, however, we humans tend to assume our sensory view of the world is universal. Nothing could be further from the truth.

Standing in the Hollywood Park paddock on a Friday night, after the long walk down a wooded, dimly lighted bridle path from the stable area, a horse can be forgiven if he begins to freak out.

Nothing appears the same as it did two weeks before, when he ran on a warm and sunny Thursday afternoon. Forms emerge from shadows. Cars blur past and headlights flicker just the other side of the porous perimeter fence.

"A horse has oversized retinas that magnify objects such that they appear 50 percent bigger than they are," writes Dr. Karen Hayes, DVM. "Equine retinas also make small movements look b-i-g.

"These vision facts, coupled with his inability to focus instantly, prevent your horse from making 'logical' decisions," Hayes goes on. "Instead, they provide him with a key survival tool: visual cues that scream 'predator alert,' inciting him to react instantly and instinctually - without stopping to think - so he can put some distance between himself and the threat."

And maybe climb a tree.

Horses use their excellent senses of smell and hearing in concert with vision, then draw their conclusions accordingly. Limiting a horse's visual input by racing at night cripples one-third of his alert system. On the other hand, humans are almost totally reliant on vision to sense danger, unless they smell smoke or hear an episode of "The Osbournes" playing in the next room.

"Horses have a very strong emotional response to whatever sensory input they might receive - and the emotion is fear," writes Dr. Rickye Heffner, a professor of psychology in the Laboratory of Comparative Hearing at Ohio's University of Toledo, who specializes in mammal hearing.

"For a prey animal, which he is, this hearing acuity makes sense," Heffner notes. "In his natural environment, other animals, including predators, are the only things besides weather that generate noise. If the sound tells him action may be warranted, he'll follow with eye movement, then finally raise and turn his head so he can better focus.

"Fear triggers your horse's flight mechanism," Heffner adds. "We humans often curse it, but that hair-trigger response is an important thing to have. A horse doesn't want to be brave. If he is, a lion is likely to eat him. His best shot at survival is to run first and think later."

Night racing won't go away any time soon. That's a fact. But for the operators of those racetracks who persist in presenting Thoroughbreds under artificial light, the least they can do is understand the effect it has on the athletes, and prepare for those athletes to act as nature has designed them.