The runners of the two-horse wooden sleigh crunch and squeal on the packed snow beneath us as we start out toward the elk herd in the distance.

We are an even dozen, not counting the guide and the driver, and we are bundled in parkas and draped with wool blankets to ward off the penetrating cold of a sunny afternoon in Jackson Hole, the valley where the herd winters each year.Wyoming isn't the only place in America where you can see elk. More than a half-million of these magnificent animals roam 10 Western states and four Canadian provinces. Several states east of the Mississippi also have small herds, including Pennsylvania, which has more than 200 head in its remote north-central mountains.

But Jackson Hole is probably the best place to see them. Each autumn, close to 7,000 elk come down from the mountains to the National Elk Refuge here after the first major snowfall cuts off their food supply.

The refuge, run by the U.S. Fish and Wildlife Service, is a five-minute drive from the town of Jackson - so close that elk occasionally wander downtown, despite a 10-foot fence on the perimeter. And along the main road leading from the airport to town, it's sometimes possible to see eagles, ravens and coyotes dining on the carcasses of elk that could not make it through the long winter.

"This is a wild elk herd," says Steve Cooley, Wildlife Service interpreter and guide, as we slowly move across the flat valley floor. "Nature pretty much takes care of things here, and winter mortality in the herd is a part of that."

"You just let them lie there on the ground?" asks a woman in the back of the sleigh.

That's it, says Cooley, unless it's determined that the dead animal is diseased, and then it is removed.

The "cleanup personnel" - those ravens, eagles and coyotes - take care of most carcasses, says Cooley. In fact, as he talks, a very healthy-looking coyote is skulking along the edge of the herd, no more than 100 yards away.

"They're looking so good because there's been plenty of free lunch this year," adds Danny Luton, the sleigh driver and concession owner who has been taking tourists into the middle of the herd for 16 years.

Nature does get a little helping hand, however. The herd's diet of grass, often foraged from beneath snow and ice, has been supplemented by people since as far back as 1912, when the refuge was created. For many years, baled hay was used; today it's alfalfa pellets, which are not only easier to handle but also less wasteful. A typical animal eats about seven pounds of pellets a day.

If that sounds like a lot of alfalfa, consider the elk's size: The bulls, which have large, branching antlers, can stand 5 feet tall at the shoulder and weigh up to 800 pounds; cows weigh from 450 to 600 pounds. Only the moose is larger.

Because of those large antlers, it's easy to see as we get closer to the herd that the males are off in their own groups, and the females and calves in theirs. "Why is this?" somebody asks.

"Because they're guys," The Voice in the Back quickly pipes up, to many chuckles. "That's sort of it," says Cooley. "It's just the way herds work. Anytime except the rut, the males are going to be off by themselves."

"I told you," says The Voice.

As we slip slowly into the edge of the herd, cameras click, and a few elk stir, but mostly the scene remains placid: Big knots of these brown-grey animals (elk are brown, with light rump patches, but their coats gray out in winter) munch on tufts of grass, paw the snow in search of some, or lie quietly in the sun, seemingly oblivious to the sleigh. "They're accustomed to it," says Cooley.

"But you should see them run," adds Luton, who says they can reach 45 miles an hour. "It's amazing how these bulls can go through the brush with their huge racks when you're hunting them."

"Hunting them?" says The Voice, quite aghast. "What do you mean - hunting them?"

"Yes, indeed," says Luton. An elk is quite a trophy animal, and there's an annual lottery for hunting permits in Wyoming. "It helps keep the herd in check," he adds.

Silence from the rear.

The elk mate in early fall, and calves are born in June, explains Cooley. The bulls lose their antlers in March and April, and the local Boy Scouts come around to collect them and sell them. Tourists buy them. So do people who carve them for crafts. There's also an Asian market, says Cooley, because in that part of the world, some people believe powdered antlers are a powerful aphrodisiac.

"An aphrodisiac?"

"Yes, ma'am," says Cooley through tight lips, while Luton shakes the reins and smiles up front.

Elk herds once roamed much of North America. But the pressure of civilization was such that by the turn of the century, the range was reduced mainly to mountain regions of the West - the only place left with the huge undisturbed territory that elk need to survive.

Today, according to the Fish and Wildlife Service, most elk in the West range on public lands in summer, but their winter ranges in privately owned valleys are being threatened by development. This includes Jackson Hole, where the service continues to buy up land in an attempt to safeguard the herd's migration route.

Our trip through the placid herd is about as exciting as such journeys can be - hardly akin to bopping down a ski slope at 40 m.p.h., but memorable as a rare winter spectacle that has survived the centuries.

Now on the fringe of the herd as we head back toward the stable and the refuge visitor center, we see a few more coyotes slowly loping nearby, looking relatively fat, with rich, shiny coats.

"Why don't they just shoot them?" asks The Voice.