Samenvatting

Recently, Lévy walks have been put forward as a new paradigm for animalsearch and many cases have been made for its presence in nature. However,it remains debated whether Lévy walks are an inherent behavioural strategyor emerge from the animal reacting to its habitat. Here, we demonstratesignatures of Le ́vy behaviour in the search movement of mud snails (Hydrobiaulvae) based on a novel, direct assessment of movement properties in anexperimental set-up using different food distributions. Our experimentaldata uncovered clusters of small movement steps alternating with longmoves independent of food encounter and landscape complexity. Moreover,size distributions of these clusters followed truncated power laws. These twofindings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidencethat such multi-scale movement is an inherent behaviour rather than resultingfrom the animal interacting with its environment.