06/15/2026
HEY ALL!
Have you ever seen the ancient game drives built right on the Continental Divide by Paleolithic hunters?
If not, then hike the divide this summer. Soak up the huge views. Lean hard against the wind. Try not to step on the millions of tiny flowers (impossible). Exult in that Rocky Mountain high, and then take a close look: Two, three rocks stacked atop one another. You might think they're cairns put there to guide hikers along the Continental Divide Trail, but you'd be wrong. Look again: Circles of stacked cobbles and long lines of small lichen encrusted boulders, 6 inches, a foot, three feet high, running for hundreds of feet in various directions. Way up here, in the middle of nowhere, someone has taken the time to build small stone walls all over the place.
These walls were built by long vanished hunters hoping to funnel unwitting animals toward their sharpened spears. Evidence of similar "game drives" have been found across North America, including the more famous "jump drives" on the plains (where buffalo were stampeded over a cliff to their collective doom) and dozens of other varieties where animals were netted, corralled, or otherwise ambushed. The tundra ridge that makes up the eastern horizon of the Fraser Valley contains an exceptionally dense concentration of them—at least 80 hunting blinds, 1,935 meters of walls, and 15 cairns and two additional cairn lines have been recorded along 30 mile stretch of mountains between Berthoud Pass and Rocky Mountain National Park, more than half of them overlooking the Fraser Valley.
The game drives along The Divide are awe inspiring in their antiquity and scale, at least once you figure out what you're seeing—at a glance they look like the work of frost heaving tundra soils rather than the efforts of ancient humans huffing and puffing in the thin air. Many are quite old—five, six, seven thousand years old, and predate the more famous Anasazi ruins in southwest Colorado by millenia. Each stone was deliberately chosen and placed by the hands of a human who has left no other sure trace of his existence, always a humbling thought. The walls are a sight to behold,Yet at the same time, there is something intuitive about them that makes a person feel as if he or she could have easily pulled off a similar feat: Yes, of course, stone fences; why didn't I think of that?
The concept is simple: Wait patiently for animals to migrate through, or be proactive and scare up game, mostly deer and bighorn sheep at this altitude, and harry them to the rock walls, which steer the animals towards hunters concealed behind circular stone blinds. Sounds easy, but while the construction of these drives—stacked stones—is, indeed, primitive, their design and ex*****on are surprisingly complex.
Before a single rock was moved, a number of details had to be worked out. For starters, there needed to be animals to hunt, which required a nearby (but not too nearby) patch of good grazing land, and this grass had to be upwind from the walls and waiting hunters. After establishing the presence of game, the topography was examined closely. Were there cliffs or other natural barriers that would help block animal movements? Boulders or patches of gnarled spruce krummholz for hunters to hide behind? An existing game trail that the intended prey would instinctively follow? As any modern day, ski bumming mason could tell you, building stone walls at high altitude is hard work, and any natural features that could minimize the work load and maximize the efficiency of the drive were surely included in the blueprint.
Big rocks and steep cliffs are fairly reliable parts of the landscape, but more nebulous aspects of a potential drive site were also taken into account. One of these was snow. Depending on the severity of the winter storms, patches of summer snow above tree line can vary greatly in size and depth, but the contours of the land form patterns of shade and wind that create snowfields in the same place year after year. By mid-summer, just as ancient Coloradans would have arrived in the high mountains for the timberline hunt, these remnant snow drifts would have settled into firm banks that provided animals with a smooth path across the shattered rocks that make up much of the alpine terrain, while the long, wind sculpted cornices dangling high above eastward draining cirques could block off escape routes and preclude the need for laborious stone work.
The other variable, and one that could make or break a successful game drive, was the wind. Modern day hunters have an array of optical technology and high powered rifles at their disposal that enable them to bag a trophy elk from hundreds of yards away, but every expensive gizmo can be rendered instantly useless by a simple shift of the wind. A whiff of human will send an entire herd of elk scurrying for safety in a flash, which means that hunters need to be downwind from their intended prey—particularly if dinner depends upon a hurled spear rather than a bullet. Hunters who stalk animals can allow for changes in wind direction and adjust accordingly, but stone game drives, once built, became permanent features of the landscape and couldn’t be moved, which meant that they had to account for prevailing winds.
This too seems straightforward, for as anyone who’s hiked that stretch of mountains knows, the winds up there can howl on any given day, and they almost always howl from west to east. While this is certainly true of winds at altitude, landforms—rock outcrops, valleys, even trees—can create eddies just like a boulder in the current of a river, resulting in surface winds that blow differently, or even in opposition to, the prevailing wind. Unlike the macro-scale gales along the crest of the Divide, these localized sub-winds can be subtle, and their presence might only be revealed by being fully aware of your surroundings: the shape of the wind sculpted trees at timberline; the presence or absence of mosquitoes; even the growth patterns of lichen on the shattered rocks underfoot. Get it right and you’ve got the advantage, but overlook a single detail and you’d go to bed hungry.
A game drive at Devil’s Thumb Pass demonstrates just how complex one of these operations could be. It consists of 25 separate hunting blinds and 40 small cairns settled amongst a series of walls hundreds of yards in length, the whole shebang unfolding along a quarter mile stretch of flowery tundra. The walls are surprisingly low—just three feet at their highest points, and much lower in sections of the ridge lacking easily gathered stone, but they provided a psychological barrier that prompted animals to turn in the desired direction, an effect that could be heightened by stationing people behind the walls at strategic points and having them stand and wave their arms as the animals approached, or by decorating the walls and small cairns with some kind of flagging, perhaps strips of tanned hide or bundles of grasses that waved in the breeze. On the east side of the drive, the scoop of a glacial cirque causes prevailing west winds to spin around into a ground level easterly breeze, which meant that animals could be driven from either side of the mountains without catching the scent of the hunters lying in wait. Finally, cliffs and large cornices of snow were utilized as natural barriers to help lead animals in desired directions. It is a large site, and archaeologists estimate that it took the well-planned and cooperative efforts of 30 to 35 people to operate the drive at its full potential, which suggests that all but the very youngest and oldest members of the clan played a role in a successful hunt.
NOTE: if you check these out, please be respectful. Some of them have been there for 5, 6, 7 thousand years old. Take photos, but don't take or move the rocks. Sit quietly and soak up the memories and stories that these places share with those willing to engage them respectfully.
