Sharks also have a unique and highly specialised bioelectrical sensory system scattered over the front of their heads that not only helps them detect and home in on prey, but may help them navigate relative to ocean currents and the earth's magnetic field. This system is called the ampullae of Lorenzini. By using this system sharks can find their prey, at least at close range, without seeing or smelling them. They can sense stingrays and flounder buried in the sand and strike with great accuracy.