The population of a predator will be affected by the population of the prey on which it feeds. It has been suggested that this gives rise to regular cycles in prey and predator populations. A low prey population means that there will be little food for the predators. The prey population will therefore increase, providing more food for the predators. The predator population increases in turn and reduces the population of its prey. The result of this is that both predator and prey numbers oscillate as shown below. There is some debate over whether this is really what happens, because prey populations show regular fluctuations even in the absence of predators.