Plants and animals of the mountain world:
1 Prairie falcon 2 Pika 3 Yellow-bellied marmot 4 Cushion buckwheat 5 Whitebark pine 6 Subalpine fir krummholz 7 Dwarf willow 8 Pixie-cup lichen 9 Black rosy finch 10 Alpine forget-me-not 11 Moss campion 12 Haircap moss
Wary bighorn sheep are the largest mammals of the high mountain realms. The male’s horns, curved back, down, and around, may cap a 135-kilogram (300-pound) body. Sheep wear thick, tannish-gray hair. Their specialized footpads enable them to scale rock that might stymie a roped alpinist. Rams and ewes hold to separate bands except during the mating period. Generations of sheep will occupy the same range. The Teton population, numbering between 100 and 125 animals, is wary because the sheep are hunted in fall on adjacent national forest lands. Hikers and climbers occasionally see them on the range’s east side, but you will not see bighorn sheep from your car except sometimes in the winter when they may move down into Jackson Hole.
Autumn aspens lend what prospectors never found in this valley—large touches of gold.
The Valley
With the Louisiana Purchase treaty signed, President Thomas Jefferson wanted to know what he had bought, so he sent the Lewis and Clark Expedition overland to the Pacific in 1803 to find out. On the return trip John Colter left the expedition along the Yellowstone River to stay in the West and join a trapping venture. He is considered the first white person to discover what is now Jackson Hole. Colter supposedly wandered through this high, mountain-encircled valley—trappers called such valleys holes—in the winter of 1807-1808. Colter was soon followed by other trappers, and 40 years later the trappers were followed by homesteaders. Several homesteaders became dude ranchers, and their dudes were followed by vacationers, who now number nearly three million each year.
The flatness of Jackson Hole comes as a surprise, considering that the Teton Range was formed by a fault-block process. You would expect a deep valley, but it has been filled repeatedly by rock debris transported by glaciers and their meltwaters. The Snake River does little cutting into the valley floor today. The flat areas above the river, called benches, were carved out when the river had the torrential force of glacial meltwater. The river’s north-south flow shows that the valley slopes southward. The valley also tilts westward, toward the fault that gave rise to the Teton Range. For reasons not fully known, the valley has sunk more than the mountains have risen. We know this because a sedimentary cap of rock atop Mount Moran—nearly 6,000 feet above the valley floor—was once connected to the same rock layer that now lies an estimated 24,000 feet below the valley surface.