  Recent studies suggest that non-cooperative behavior such as cannibalism may
also be a driving mechanism of collective motion. Motivated by these novel
results we introduce a simple model of Brownian particles interacting by
pursuit and escape interactions. We show the onset of collective motion due to
escape and pursuit response of individuals and demonstrate how experimentally
accessible macroscopic observables depend strongly on the ratio of the escape
and pursuit strength. We analyze the different impact of the escape and pursuit
response on the motion statistics and determine the scaling of the migration
speed with model parameters.
