By 1924 the deer population was estimated at 100 000. This was far more deer than the food on the Kaibab Plateau could support. By 1939 the population of deer had shrunk to about 10 000. This was still higher than the original population. It can be seen from the Kaibab deer population story that predators perform an important function within a community.
Predators are usually able to catch the weak, unlucky, old and sick.
As a result of being preyed on, the prey species remains healthy. The removal of the predators meant that more deer survived, and these were left with a limited food supply. Without sufficient food many deer began to starve. The lesson from this example is that we must be careful what changes are made to an ecosystem. Even a seemingly small change can at times have a large impact on an ecosystem.