In 1906, the Kaibab Plateau in northern Arizona was declared a federal game refuge by President Theodore Roosevelt. Before this time, the Kaibab was home to mule deer, cattle, sheep, and a variety of predators. The approximately 4,000 Rocky Mountain deer were an important source of food for the wolves, coyotes, bears, mountain lions, and bobcats that lived on the Kaibab and competed with sheep, horses, and cattle for the limited grass resources of the plateau.
When the game refuge was created, all deer hunting was banned in an attempt to protect the "finest deer herd in America." In 1907, the U.S. Forest Service began to exterminate the natural predators of the deer. With the deer freed from the checks and balances of predators, the population began to multiply. By the early 1920s, scientists estimated that there were as many as 100,000 deer on the plateau.
Sheep and cattle were also banned from the Kaibab. Signs of overgrazing were everywhere, and disease began to attack the crowded deer population. Hunting was reopened, but it was not enough to reduce the number of deer. Some estimate that as many as 60,000 deer starved to death in the winters of 1925 and 1926.
Two scientists exchange views about "The Kaibab Deer Incident: A Long-Persisting Myth."
Scientist A
The Kaibab Plateau should be a lesson to everyone about the disruption of the predator-prey relationship1. This is a classic example of predator control hurting the very species that the wildlife biologists are attempting to help. If the predators had not been removed from the Kaibab Plateau, the deer population would have grown under normal conditions and would not have been subjected to the cruel fate of starvation and disease. This is a moral case that should be heeded by all biologists when considering predator control and presented to biology students in their studies of predator checks in population dynamics2.
Scientist B
Predator removal is only a small part of the disaster on the Kaibab and has been grossly overdramatized3. The deer population on the plateau grew rapidly because of the increase in food supply after the removal of competitive species. With no sheep and cattle to compete with for grazing, the environment could readily support more deer. The increased food supply allowed the population to grow quickly and to fall just as quickly due to the density-dependent factors of starvation and disease. In fact, data about the peak total number of deer on the plateau are unreliable, and there may have only been 30,000. The factors are more complex than early ecologists believed, but the lesson is still valuable.
*Based on data from C. John Burk, "The Kaibab Deer Incident: A Long-Persisting Myth," BioScience 23, no. 2 (1973): 113-14.45678910