Keeping a safe distance so as not to spook the herd in the wrong direction, several Native American hunters rise out of their hiding spots and show themselves in an effort to begin driving the bison downhill.
It's a warm autumn day, centuries before any European settler arrives in what will become east central Idaho.
Spying the men advancing toward them through sagebrush and golden bunchgrass waving in the lazy autumn breeze, the dark bovines and their young reddish calves begin a slow retreat away from the danger.
Suddenly, more hunters—called runners—appear on both sides of the bison, now effectively flanking the herd on three sides. As recognition of this new threat enters their bovine brains, the increasingly nervous herd begins a steady trot down the sloping tableland, their only escape visible in the distance ahead.
Jostling for position—the whites of their eyes betraying their alarm—the massive beasts, some weighing as much as 2,000 pounds, hit their stride as more runners materialize even closer on each side. Long, narrowing piles of sagebrush and rocks help keep the corralled herd thundering toward the river valley beyond.
Suddenly, bison at the front of the herd find themselves bunched up on the edge of a shear 60-foot cliff face that only moments ago was invisible to them. But it's too late. Powerful bison at the rear of the herd—unaware of the danger ahead—keep pushing out of fear of the pursuing hunters. One by one and then perhaps in pairs, the bison fall off the cliff face to the rocks below.
Studying an Idaho anomaly
Standing above the same cliff face last Wednesday, National Park Service archeologist Ken Cannon of the Midwest Archeological Center in Lincoln, Neb., described the scene some archeologists believe may have taken place for centuries near the present-day community of Challis along the banks of the Salmon River.
With long thrusting spears or bow and arrow in hand, hunters staged at the bottom of the cliff would have finished off the surviving members of the herd as the tribe's women prepared for the day's most physically demanding chore—butchering the bison. Heavy bison hides would be set aside for teepees, while the thousands of pounds of protein-rich meat would have been cut up for drying—all in preparation for the cold winter months ahead.
"They would dispatch them and butcher them up," he said. "It would have been a tremendous event to witness."
Along with his wife Molly Boeka Cannon, a Ph.D. archeology student at the University of Nebraska, Ken spent much of June working on an archeological excavation at the base of the Challis-area cliff face. The couple was assisted by eight high school students from around the country selected to take part in the Earthwatch Institute's Student Challenge Awards Program, which is funded by The Durfee Foundation of Santa Monica, Calif.
Students selected for the program work with scientists in disciplines like astrophysics, microbiology and archeology.
The Cannons' work near Challis seeks to corroborate or dispel the early 1970s work of another archeologist—Robert Butler of Pocatello—who theorized that horseback-mounted Shoshone Bannock used the tall cliff as a bison jump site. Based on the artifacts he unearthed during his own dig there—including bison bones and obsidian projectile points—Butler estimated that up to 20-30 bison were dispatched at the site in a single event. But, lacking any of the sophisticated equipment to date the bones and other artifacts, Butler could only guess at the site's age, Ken said.
In the end, Butler concluded that the jump site was used more recently, during the 1800s.
But based on new excavation at the site during the past two summers—as well as complex carbon dating of old bison remains—the Cannons now believe the Challis bison kill site is more ancient, perhaps as much as 850 to 900 years old.
One of the primary problems Ken has with Butler's theories is the idea that Shoshone Bannock were hunting bison at the site well into the 1800s. He said that conflicts with the region's accepted date of bison extinction, estimated at around 1840. Another problem Ken has with the more recent theory of the site is that the "bison lifestyle" of the Shoshone Bannock tribe was essentially lost by that time.
"They were on the reservation," he said.
Ken did note that there is evidence that large herds of bison still roamed across the region into the early 1800s.
Although it may be hard to believe today, massive herds of the shaggy beast once grazed freely across much of southern Idaho on the wide-open Snake River Plain and up many of the northwest-trending valleys we today call the Birch Creek, Little Lost River, Pahsimeroi and Big Lost River valleys. As late as 1828, renowned Western fur trader and explorer Alexander Ross, passing through the vicinity of the Big Lost River Valley near present-day Challis, reported seeing a herd of bison he estimated at 10,000 animals, Ken said.
The herds are now gone, their closest remnants living in Yellowstone National Park in northwest Wyoming.
Part of the Cannons' research is attempting to determine how common these herds of bison were in present-day Idaho. They're also seeking to explain how population size may have ebbed and flowed and how this may have impacted the Shoshone Bannock who relied on them for sustenance.
"How the bison populations have waxed and waned in response to (natural) climate change," he said.
Ken's primary interest as an archeologist has been focused on the bison culture of Northern Great Plains tribes. He said the Challis site stood out to him because of its vast distance from other known bison jumps, which are thought to only exist on the Northern Great Plains, far from the Butler's site.
"It's the furthest west traditional bison jump site," he said. "It's an outlier."
Part of the problem the Cannons and their high school helpers have had to face is a general lack of records from Butler indicating where he dug and what convinced him that "drive features" existed on the sloping tableland above the cliff.
Using advanced surveying equipment, Molly Cannon has been working to establish a digital record detailing objects like boulders or rock piles on the hillside above the cliff that may have been used by the ancient hunters to keep bison heading towards the cliff face. She said the equipment shoots a laser to a prism set next to the likely-looking object which then bounces back to her, measuring the distance.
Once back in their laboratory, the Cannons will analyze the information to determine if any discernable patterns show up that would indicate the ancient bison driveway did exist.
Clues to an ancient trade network
Based on the early results of their work, the Cannons question how extensively the Challis cliff may have been used by hunters as a bison jump. But that's more of a gut instinct than confirmation, Ken said.
"We can say bison were killed here. How they were killed is our problem."
Perhaps just as interesting is what the archeological evidence at the site does clearly indicate. Artifacts taken from a nearby campsite Butler began excavating in the 1970s suggest hunter-gather peoples used the site not in a factor of hundreds of years ago, but thousands. What drew them to the site—robust runs of salmon in the nearby river, the area's more moderate weather patterns, or something else—just isn't clear, Ken said.
"Something was causing people to come back year after year," he said. "For 6,000 years or so."
Artifacts collected at the site, like obsidian projectile points—which had as their source obsidian mined in known quarries outside of present-day Idaho, analysis indicates—point to a sophisticated trade network among various tribes that stretched back hundreds of years or more, Ken said. The traders would have also been exchanging food items back and forth, he said.
"Bison was going to the West Coast and salmon was going to the plains," he said.
How the inhabitants of today's Challis region fit into that network is just another question the Cannons would like to answer.
Ken said modern people tend to consider ancient hunter-gatherers unsophisticated, a belief that isn't borne out by archeological evidence.
"The amount of knowledge they were carrying around in their heads was amazing. Hunter gatherers are us just without all the stuff."
While very little archeological research has been done in east central Idaho—a landscape of remote mountain ranges like the Lost Rivers, Lemhis and Beaverheads—the aridity of the region has likely preserved clues to the area's human past quite well, Ken believes. It's an idea that excites archeologists like the Cannons, who have also conducted archeological surveys in places like the Jerry Peak area in the eastern Boulder Mountains.
"This part of Idaho is just a big black hole in terms of research," he said.