Two tons of attitude: Wyoming’s bison launch the rut

If you’ve never heard a two-thousand-pound bull bison bellow across a sage flat, August in Wyoming will fix that. America’s largest land mammal is the first of the hooved crowd to kick off fall courtship, with the bison rut sputtering to life in July, roaring through August, and lingering into September. By the time elk, moose, and pronghorn are just getting warmed up in September — and deer and bighorn sheep much later — the bison have already turned the valley bottoms into dusty arenas, Casper Star-Tribune reports.

The show is primal and oddly graceful: massive, dark silhouettes rolling in wallows, geysers of dust hanging in the late light, bulls shadowing cows and shouldering rivals. Watch long enough and you’ll catch a bull lift his head and curl his upper lip — the flehmen response — tasting the air for a receptive female like a sommelier with a very weird assignment. It’s impressive from a distance, and that distance is non-negotiable.

It’s tempting to think the bison that thunder across Yellowstone and Jackson Hole are one sprawling super-herd, but they aren’t. They’re distinct, with little interchange. The Jackson Bison Herd, in particular, has a backstory that says as much about people as it does about wildlife. Bison once ranged across all of Wyoming and far beyond, their numbers in the hundreds of millions. By the mid-1880s, relentless slaughter had erased them from the landscape everywhere outside Yellowstone National Park.

Jackson Hole wouldn’t see them again until 1948, when 20 bison were trucked to a fenced exhibit called the Jackson Hole Wildlife Park near today’s Oxbow Bend in Grand Teton National Park — a place where visitors also ogled elk, moose, deer, and pronghorn. The bison, being bison, made a habit of slipping the fence. For two decades, escape and roundup became a ritual. In 1969, park officials finally quit playing gatekeeper. The escapees stayed free, and a modern, free-ranging Jackson Hole herd was born.

Freedom came with a discovery. In 1975, the herd found its way to the National Elk Refuge on the south end of the valley — then found the supplemental hay intended for elk, a winter practice dating to 1912. With easy calories and less winter die-off, the herd boomed. By the mid-1990s, Jackson bison were nearing 1,000 animals. They turned up on private horse and cattle feed lines and sometimes gored livestock. They had to be shooed from the emerald fairways of golf courses and the lawns of riverside homes from the Snake River to the town of Kelly. It was clear the population needed to be reined in.

Wyoming’s go-to tool for managing big game is hunting, and there was no shortage of interest. But bison hunting on the National Elk Refuge ran into legal headwinds. Through a lawsuit, the Fund for Animals blocked hunts there until an interagency plan finally cleared the way in 2007. By then the herd had swelled to roughly 1,200. In the years that followed, hunters helped managers bring numbers back to the objective of about 500, where the herd hovers today.

All of which sets the stage for the late-summer spectacle you can see right now. In Grand Teton National Park and the surrounding valley, dust plumes mark wallows, cows string out across sage, and bulls — these two-ton mood rings — announce themselves with grunts you feel in your chest. Yellowstone’s herds run on a similar clock, but remember: they’re separate stories playing out in parallel, not one continuous herd.

By early to mid-September, the baton passes to elk, moose, and pronghorn. Their rutting calls and clashes carry into October, with mule deer following in November and bighorn sheep sparring from late November into December. Bison just happen to fire the opening salvo of the season.

For all the management debates and the messy history that got us here, Wyoming remains one of the few places on Earth where you can watch truly wild, free-ranging bison on their own terms. In late summer, that means dust, noise, and a reminder that “wild” isn’t a museum piece — it’s alive, loud, and very much in charge.