© Prof. Graeme Hays
Barrel jellyfish are big. Weighing almost 30 kilograms, the creatures need a lot of food to fuel their massive size. As a result, the gelatinous blobs spend a lot of time floating up and down in their home waters, with movements that change over time.
Because the jellies' movements didn't seem to be consistent, scientists didn't think Rhizostoma octopus sought food using Lévy walks, a series of small steps mixed with long hops that have been shown to be an efficient foraging strategy for honey bees, sharks and even humans.
A closer look at barrel jellies' diving patterns, however, suggests that they use a new kind of Lévy walk with the help of water currents. The results, which appear August 6 in the Journal of the Royal Society Interface, also imply that the family of Lévy walkers could extend to include pollens, seeds, mites, spiders and insect larvae surfing air currents on a warm day.