IN THE LATE WINTER SUN, YELLOWSTONE NATIONAL PARK’S BLANKET OF SNOW IS BLINDINGLY WHITE. THE GREAT SHAGGY BEASTS— BISON, IN THEIR THICK, BURNISHED WINTER COATS—THRIVE IN THE GLARE. A FEW YARDS FROM WHERE I STAND ON THE ROAD, a small group is gathered, sweeping their upturned horns from side to side, grunting softly as they plow away the snow to graze. I’m transfixed, so it takes a minute to notice the hundred or so more scattered in the valley ahead of me. Across the steep rise of the Gallatin Range, bushes dotting the ridge come into focus; each, I realize, is a buffalo, lumbering out of the mountains toward lower elevation.
Each winter, Yellowstone’s bison move from the high country in groups of a few dozen, seeking better feeding grounds. The evidence of wild bison migration is etched into our continent, where the movement of vast herds shaped the land. The countless pounding hooves formed wide passages called buffalo traces, as the beasts followed watersheds and ridgelines to new territory. The early pioneers followed these paths—through the Cumberland Gap in the Blue Ridge Mountains, across the Ohio River near Louisville, and the Vincennes trace through Indiana and Illinois— to settle the West.
Of course, these places have long been purged of wild buffalo. By the 20th century, westwardmoving colonizers, a thriving hide- hunting trade, and efforts to wipe out native populations by diminishing their primary food sour