YELLOWSTONE NATIONAL PARK, Wyo. - Dawn ... low clouds ... swollen river. Like a field of dark toadstools the herds of resting bison take shape across the water. Above them on the grassy benches elk begin to move - cows and calves, a few of the very young ones still hobbling. Geese fly down the river, yakking and excited, over a sandhill crane still as a statue.


I know there are grizzlies moving between the aspen groves across the river, hunting elk calves, but it's hard to keep my binoculars trained on the hillsides, as I've done for so many springs.


Last night one of Yellowstone's new wolf packs, Crystal Bench, killed an elk calf just a half mile from where I've parked my car. Ravens dot the remains and, like a beacon, draw passing cars as the morning brightens.


Eventually the occupants of a dozen cars wait with spotting scopes trained across the Lamar River. An hour goes by, 90 minutes. Jason Wilson, a Virginia contractor who has spent 26 springs in the park observing wildlife, sings out, "Wolf, left to right, behind the cottonwoods."


And there he is: coal black, tail streaming, long legs slightly stiff as he bounds along the river bank - an alpha male. In another moment a silver-gray female appears behind him. Then four yearlings, three black, one gray, romp along, a tumble-down, jostling group which stops to bite and cuff at each other, one of which breaks off to loll on its back, paws massaging the air.


My skin crawls with goose bumps. My hair stands erect on my neck. Those are wolves! This isn't Alaska, Canada, or Siberia. This is Wyoming; this is my home.


As the six wolves gather and touch noses, tails wagging, seemingly plotting strategy, it is immediately obvious why today none of us has been searching for grizzlies. Powerful, and, when they want to chase elk, incredibly swift, grizzlies can't match the social dynamics of a wolf pack. It's as if the park has been electrified, becoming an American Serengeti complete with coursing predators and more alert prey.


The elk, necks stretched forward, ears cupped, watch the wolves carefully. A dozen bison cows huddle their calves closer, and, when the wolves disappear into a swale, the bison become so nervous that they bolt a mile and a half toward the trees, galloping the entire way.


Driving east to the confluence of Soda Butte Creek and the Lamar River, we relocate the wolves as they trot across a wide sage flat and weave their way through a hillside of burnt lodgepole. On its far side, they test two cow elk who, hair bristling, charge right back and run the wolves off.


Unfazed, the alpha female and male, and three of the yearlings (one of the youngsters has remained on the other side of the river to explore on its own) begin to circle a grassy hill. Two coyotes emerge and circle the wolves, barking and howling. What the wolves want becomes obvious as they begin to excavate the coyote's den: pups.


Stomping its forefeet, throwing its head back to wail mournfully, one of the coyotes rushes the wolves. The alpha male turns and chases. But the coyote will only retreat 50 yards. Standing, it continues to howl as the wolves take turns digging: lying on their sides, four of the wolves rest while a fifth burrows excitedly, dirt flying between its rear legs.


Eventually, each wolf is able to disappear underground. We never see them emerge with a coyote pup.


After an hour of earth-moving, the wolves lose interest and trot off; immediately a coyote inspects the den, emerges, then lopes over the top of the hill with its mate. Most of the human watchers head for breakfast.


Accompanied by Jason and his wife, Deb Lineweaver, I walk toward the river, hoping to view the den. Just as we approach the footbridge across the Lamar, two coyotes and two pups dash toward the bridge. We crouch and watch. One pup follows is parents across the high water into new territory; the other's courage fails and it heads back toward the sage.


Joined by Bob Crabtree, the park's chief coyote researcher, we make a careful sweep of the den and find no body parts. Crabtree, who has watched and studied this coyote den for five years, tells us that until this morning it contained five pups and that the Crystal Bench wolf pack will eventually replace about five of the valley's coyote packs, containing some 30 individuals.


"And deer and antelope, whose fawns the coyotes hit hard, should increase," he says. Then he shrugs fatalistically: He's bound to see some of his study groups - old friends - get eaten. It's one thing to project changes brought by wolves to an ecosystem, another to witness them. But Crabtree brightens, saying now he's got wolves to follow, to get to know, as they continue to shake up old patterns in Yellowstone.





Ted Kerasote's latest book is Bloodties: Nature, Culture, and the Hunt. He lives inside Teton National Park in Wyoming.