Sharks do not move randomly

“Our research shows that tiger sharks and thresher sharks do not swim at random, but to specific locations. In other words, they know where they are going, ”explains Yannis Papastamatiou, research director at the Museum of Natural History in Gainesville, Florida. Using acoustic transmitters implanted on several sharks, the American team brought to light real "mental maps" that the two species would use to move precisely within a radius of about fifty kilometers.

But while others, such as yellowfin tuna, orient themselves thanks to the magnetite contained in their skulls, sharks' sense of direction seems to come from more complex factors. They are assumed to use information related to ocean currents, water temperature, low frequency sounds, or smells. And "the fact that many of these trips take place at night indicates that the use of magnetic fields is also a possibility," says Dr Papastamatiou.

Not all species are affected. The Pointe Noire sharks, for example, which have also been studied, dissolve in a perfectly random fashion. And in tiger sharks and thresher sharks, researchers have found that adults use this type of directed swimming more often than juveniles and tiger sharks almost always use it over long distances. Longer and more precise journeys in adults suggest that sharks are capable of real progressive mental construction over time.