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Pronghorns evolved in the harsh, high-plains habitat of North America tens of millions of years ago alongside swift predators like saber-toothed cats and dire wolves.
Pronghorns survive harsh winters on the barest intake of sage leaves they paw from the snow. But for this sentinel herd of pronghorns, the greatest threat to its survival is a rapidly changing West.
Pronghorn follow the longest terrestrial migration in the lower 48 states. By early fall, the herd will leave Grand Teton National Park, fording rivers and climbing steep ridges to reach winter range at least 120 miles away, south of Pinedale. If the fawns endure the windblown, minus-20-degree Wyoming winter, they will make their way back to the national park in the spring.
This extraordinary migration is getting more difficult with each passing year, due to land development that is placing obstacles in the animals' way and a natural gas boom that is carving up their critical winter range.