Random patterns in fish schooling enhance alertness: A hydrodynamic perspective

Abstract

One of the most highly debated questions in the field of animal swarming and social behaviour, is the collective random patterns and chaotic behaviour formed by some animal species, in particular if there is a danger. Is such a behaviour beneficial or unfavourable for survival? Here we report on one of the most remarkable forms of animal swarming and social behaviour -fish schooling -from a hydrodynamic point of view. We found that some fish species do not have preferred orientation and they swarm in a random pattern mode, despite the excess of energy consumed. Our analyses, which includes calculations of the hydrodynamic forces between slender bodies, show that such a behaviour enhances the transfer of hydrodynamic information, and thus enhances the survivability of the school. These findings support the general hypothesis that a disordered and non-trivial collective behaviour of individuals within a nonlinear dynamical system is essential for optimising transfer of information -an optimisation that might be crucial for survival.

Locally noisy autonomous agents improve global human coordination in network experiments

“…When it comes to optimization, however, noise can help a system to reach a global optimum. For example, mutation has an essential role in evolution 17 ; error can facilitate search for information 18 ; random fish schooling may enhance survival 19 ; and cooperation may benefit from deviant behavior 7–9,20 .…”