When sharks and other ocean predators can't find food, their movement patterns shift in surprising ways that are associated with particle physics rather than animal behavior.

They abandon Brownian motion, the random motion seen in swirling gas molecules, for what's known as Lévy flight – a mix of long trajectories and short, random movements found in turbulent fluids.

"It's fascinating that you get these patterns. Maybe there's more structure to things than we think, and these patterns occur not just in physics in how particles behave, but in how animals behave," said biologist Nicoloas Pade of the United Kingdom's Marine Biological Association.

Computer models suggest Lévy flight is the optimal search pattern for predators in low-prey areas, and maximizes the chance of a random encounter. But real-world studies have been inconclusive, with reports of Lévy flight countered by doubts about data gathering and interpretation.

The latest findings, published June 9 in Nature, represent the largest dataset yet gathered in search of Lévy flight in animals. The researchers analyzed 13,000,000 movements recorded over 5,700 days in 55 radio-tagged animals from 14 ocean predator species in the Atlantic and Pacific Oceans, including whale shark, blue marlin and swordfish.

As the animals went from areas of high ecological abundance to low, the equations describing their movement switched from Brownian motion to Lévy flight.

"Our analysis provides the strongest evidence yet for Lévy behavior in diverse animals ranging across natural landscapes," wrote the researchers.

The findings raise the question of where Lévy flight comes from – whether it's an instinctive or learned behavior, a property of individuals or a function of spatial distributions governed by as-yet-unknown laws – and how it first evolved.

"Animals' behavior is much more plastic than previously thought," said Pade. "They have a huge repertoire of movement strategies and patterns."

Image: 1) Movement patterns of a shark in productive (left) and unproductive water./Nature. 2) Aggregate analyses of movement patterns./Nature.

See Also:

Citation: "Environmental context explains Lévy and Brownian movement patterns of marine predators." By Nicolas E. Humphries, Nuno Queiroz, Jennifer R. M. Dyer, Nicolas G. Pade, Michael K. Musyl, Kurt M. Schaefer, Daniel W. Fuller, Juerg M. Brunnschweiler, Thomas K. Doyle, Jonathan D. R. Houghton, Graeme C. Hays, Catherine S. Jones, Leslie R. Noble, Victoria J. Wearmouth, Emily J. Southall & David W. Sims. Nature, Vol. 465 No. 7299, June 10, 2010.

Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.