The Pronghorn's Road Across the Red Desert

The wind comes down off the Wind River Mountains with nothing to slow it, and in the Red Desert it finds a country made for its purposes. The flats roll on in long gray-red waves, sagebrush and greasewood and the dry beds of old lakes, and the wind crosses them without asking. It is the oldest thing in the place, older than the cattle, older than the fences, older than the pronghorn, and it keeps the desert the way a shepherd keeps a pasture.

This is Sweetwater County, southwestern Wyoming, the country between the interstate and the Colorado line. The roads run around it rather than through it. To the south, the badlands of Adobe Town go at the earth with red knives. To the north, the Killpecker dunes build themselves in windrows and travel, grain by grain, in the direction of the wind. Over the middle of it stands the Boar's Tusk, the gutted neck of an old volcano, black and abrupt, a landmark with no town to serve.

The light in the desert is thin and exact, the way light is in a country where the air has been scoured. Sound behaves the same way. A vehicle can be heard long before it appears, and the sound hangs in the air long after it is gone. On a still day, which is rare, the quiet has an actual weight.

Wild horses run in the southern part of the desert, descendants of ranch stock that went feral a century ago. Sage grouse hold their spring dances on the old arenas of bare ground they have returned to for as long as anyone has watched. None of it is abundant. Abundance is not the country's way.

Where the Divide Splits in Two

The strangest thing about the Red Desert is the water. The Continental Divide, the long spine that tells the continent's water where to go, splits in two across this country. The two ridges throw a great basin between them, and the rain that falls into it is marooned. It runs down through alkali flats and evaporates, or sinks into the sand and is gone. Not one drop of it ever tastes the ocean.

The red is real. The soil is stained with iron, the badlands banded in rust and rose, and the wind scours it all bare so that the color sits on the surface like paint. In summer the country shimmers. In winter it goes the other way, a bleached gray under a sky that cannot decide between blue and white. Some winters the snow stays shallow because the wind carries it off. That is the detail the pronghorn have hung their whole winter upon.

The Fastest Animal in North America

The pronghorn is the last of its family, an animal with no close kin left in the world. The early travelers called it antelope, and the name stuck, but it is not an antelope. It is the fastest land animal in North America, built for a sprint no other creature on the continent can match, with wide-set eyes that take in nearly the whole horizon and a white rump that flashes like a signal when the herd runs. Its speed was shaped by a chase that ended long ago, tuned to a hunter that vanished before the first wagons came near. The speed outlived the threat.

The Red Desert is its winter country. The winds that strip the snow from the slopes leave the bitterbrush and the sage standing above the white, and the herds feed there while the mountains to the north are buried. They leave in the spring, when the days turn and the grass begins to green up along the northern routes. They do not wander. They follow a path older than the state that now owns it, older than the fences that learned to lie across it.

The route runs out of the basin, past the edge of the Green River, through the gap between the Wind River Range and the Wyoming Range, and north toward the Tetons. It is about a hundred and fifty miles one way, one of the last long land-mammal migrations left in the lower forty-eight. The timing is set by the green-up, the wave of spring growth that rolls up the elevation like a tide. The pronghorn ride that wave, ahead of it or behind it, depending on the year. The route itself does not change. The GPS collars that biologists fixed to the herds in recent years traced it, fences and all, but the collars only confirmed what the animals had been doing for thousands of years.

The Pinch at Trapper's Point

The hard parts of the journey are the ones people made. The pronghorn will not jump a fence. Its whole defense is the run, and a fence ends the run abruptly. Where the bottom wire is tight and low, a herd will pace the boundary for miles, looking for a gap it can crawl under. A fence is a wall to an animal that fears nothing but the narrow.

West of Pinedale, the country pinches. The Green River and its fields crowd the migration route between them, and the herds are funneled into a throat of open ground at the place called Trapper's Point, named for the mountain men who camped there when beaver was money. U.S. Highway 191 runs through that throat. For years the migration crossed it between the headlights, and the herds piled up while the drivers slowed and waited.

In the years that followed, the state and its partners built the animals a way across and under the highway. Wildlife overpasses and underpasses now carry the corridor over the blacktop, with fencing on both sides to steer the herds to the crossings. The pronghorn took a while to trust them, as pronghorn distrust everything new. The overpasses were accepted first, because an overpass looks like a fold of grassland. The underpasses took longer. A tunnel goes against the religion of an animal that lives by seeing the horizon.

Energy development has pressed in along the same corridor. Gas wells hum on the benchlands south of Pinedale, and the drilling roads cross the route in a dozen places. Still the herds arrive. They have made their peace with the new obstacles the way they made it with the highway, which is to say they have not stopped coming.

Ranchers in the corridor lifted bottom wires and replaced barbed wire with smooth wire in the places where the herds need to cross. In 2008 the Bridger-Teton National Forest, where the route climbs into the high country toward the Tetons, formally recognized the Path of the Pronghorn as a migration corridor — the first time a national forest had done such a thing.

The Red Desert is easy to mistake for emptiness. The maps show nothing between its landmarks but the blank of public ground. But it is an emptying house, and it fills every spring. The desert gives up its tenants, and the animals string out along the ancient route, past the scoured ridges, past the dunes, past the black tusk of the old volcano, to the funnel at Trapper's Point. The overpasses take them, the underpasses swallow them, and the highway goes on carrying its own traffic beneath the travelers who were there first.

In the fall the mountains shed them back. The same gap, the same fences, the same crossings, and the desert opens to receive them. The wind smooths their tracks, and the red country keeps its own counsel. But the road does not close. It only waits for the spring.

Photos: James St. John (CC BY 2.0)