Using statistical analysis, researchers have demonstrated that the journeys of three species—tiger, thresher, and blacktip reef shark—were not made by accident; the sharks followed some kind of path.

Scientists analysed data from tiger sharks tagged with acoustic transmitters and found they took directed paths from place to place. Other species, such as blacktip reef or thresher sharks, did not show this behaviour.

It was difficult to determine whether sharks were using so-called random or directed walks (for an explanation, see the link below), as the researchers had no way of knowing where the animal wanted to go.

However, the researchers could tell the difference between a random walk and a directed walk by examining the shape of the sharks' movements at different spatial scales.

They compared the overall distance the sharks had moved to those estimated by random walk models, mathematical equations that predict how far an animal will move if it is moving randomly at these different scales.

"Our research shows that, at times, tiger sharks and thresher sharks don't swim randomly but swim to specific locations," said research leader Yannis Papastamatiou from the Florida Museum of Natural History in Gainesville.

"Simply put, they know where they are going."