Darwin or Einstein, who is making them move?

Background/Question/Methods

Brownian motion has been the general explanation for diffusive movement in animal ecology. However, the use of Brownian motion as a description of large-scale animal movement has been challenged by empirical studies, which show that many searching animals are found to do a Lévy walk, in which short movement steps are alternated with long moves. Currently, there exist significant controversy about which search model, Brownian or Lévy walks, best describes animal movement on both individual and population levels.

Results/Conclusions

We present a combined experimental and theoretical study on the movement of mussels during the process of spatial self-organization, in which young mussels aggregate into a pattern of regularly spaced clumps. Our results suggest that observed mussel movement is determined by the interplay of Darwinian selection for efficient movement, and encounters between moving individuals, thereby following Einstein’s theory for Brownian motion.