When it comes to remarkable feats of migration, you’ll often hear about birds or salmon. But many sharks also undertake impressive journeys across the oceans, from great white sharks—some of which travel from South Africa to Australia and back—to lemon sharks that can find their way home to a tiny island in the Bahamas.

For decades, scientists have wondered how these fishes pull this off. Many species have a superior sense of smell, but although it may help them to orient during the final stretch, it’s unlikely that smell alone could guide them across large distances. That’s why many experts believe sharks navigate by sensing Earth’s magnetic field, perhaps using