The Kaibab: Ninety-Four Miles to the Other Rim

The Kaibab Plateau is an island. Not literally, but ecologically. Surrounded on all sides by canyon and desert, the plateau sits roughly a thousand feet higher than the South Rim across the canyon, cut off from the surrounding landscape by the Grand Canyon to the south and by desert valleys on the other three sides. Animals that evolved on the Kaibab over thousands of years of isolation diverged genetically from their counterparts on the South Rim. The most famous example is the Kaibab squirrel, a tassel-eared species found nowhere else on Earth, which descended from Abert's squirrels that were isolated on the high plateau as the climate warmed after the last Ice Age.

Kaibab National Forest covers the plateau and extends south below the canyon to a separate unit near Williams. The north unit, roughly six hundred thousand acres of spruce-fir and ponderosa pine, is the forest most visitors encounter when they drive State Route Sixty-Seven from Jacob Lake to the North Rim. The road itself crosses the plateau through about forty-three miles of forest before reaching the canyon rim.

The Kaibab deer population, in the nineteen twenties and thirties, became one of the most instructive cautionary tales in American wildlife management. After predators were eliminated from the plateau, the mule deer population exploded, exhausted the available browse, and then collapsed in a mass starvation event. The story is so frequently cited in ecology textbooks that the actual numbers have been disputed repeatedly, but the basic dynamic, what happens when a prey population loses its predators, entered the American environmental consciousness through the Kaibab. The wolves and mountain lions are gone. The lesson stayed.