Animals that randomly reorient at cues left by correlated random walkers do the Lévy walk.

For many years, correlated random walks have been the dominant conceptual models used in describing nonoriented animal movements. Here it is shown that Lévy walk movement patterns will arise from animals that randomly reorient on detection of odor trails and/or scent marks left by correlated random walkers. The emergent Lévy walk movement patterns are advantageous when one is randomly searching for sparsely distributed resources. Consequently, there will be strong selection pressures for the aforementioned reorientation process when resources are sparsely distributed within unpredictable environments inhabited by correlated random walkers. This selection pressure may drive the evolution of Lévy walk strategies in these landscapes. The mechanism may account for the Lévy walk movement patterns of microzooplankton in the presence of mobile phytoplankton and those of a species of African jackal that scavenges within landscapes inhabited by other animal species. These findings show that Lévy walks and fractal scaling do not exist outside of the correlated random-walk paradigm, as is widely thought, but are instead natural consequences of it.