We bounce in the truck along a furrowed road, through a mud slick and up to a bluff that looks out to the curve of the Earth.
In the days before horses and guns, Plains Indians chased buffalo off this steep embankment to their deaths. It's late in May, late in the afternoon, and the light has taken on a rich, nostalgic cast. Damien Austin, a former zookeeper with rectangular glasses and a rectangular fringe of hair, extends his hand across the humped expanse of prairie. "Just imagine grizzly bears running around out there," he says.