28 Feb 2008

How sharks find their next meal


Ever wondered how marine animals find their next meal?

Apparently, the same way we do our shopping: we don't wander aimlessly but go down the road and, if we don't find what we want, make a couple of longer trips downtown. This special type of random motion is known as a Levy walk.

Ecologist David Sims of the Marine Biological Association laboratory in Plymouth, U.K., and collegues have found evidence of Levy walks analyzing more than a million dives of 31 large marine predators - including sharks, fish, sea turtles and penguins - as they apparently hunted for food.

The team also conducted computer simulations showing that if prey is scattered in the ocean, but concentrated in clumps, repeated short dives with an occasional much longer plunge would be the best strategy to find it.

This research was published today on Nature.
Sims D.W. et al. 2008. Scaling laws of marine predator search behaviour. Nature 451:1098-1103. doi:10.1038/nature06518

Eleonora de Sabata