Asked by: Rod Clarke, Isle of Man
Salmon use the Earth’s magnetic fields like a map. Unlike birds that can learn to navigate from their parents, salmon are left to their own devices from the moment they’re born. They inherit a built-in magnetic sense from their parents and use it to navigate thousands of miles out to sea, where they grow up. Near the end of their lives, salmon remember the magnetic fields they encountered when they first entered the sea as youngsters and navigate their way back to the exact same stream where they were born, to spawn and die.