Chapel Hill, United States - November 20, 2025 University Of North Carolina At Chapel Hill – Researchers have shown that hatchling loggerhead turtles feel the Earths magnetic field when using the magnetic map they are born with. In Journal of Experimental Biology, the team explains that this sense tells the youngsters where they are on their long migration routes. Hatchling loggerheads begin their journey from the beach where they were born, travelling thousands of kilometres over decades. They carry a magnetic compass that tells them the direction they are moving and a magnetic map that reveals their position. Animals can sense the Earths magnetic field in two ways. Light sensitive molecules might allow them to see the field, while tiny magnetite crystals in the body could help them feel it. Scientists wanted to learn which of these guides the turtles during their odyssey. Kayla Goforth, Catherine Lohmann, Ken Lohmann and colleagues had recently discovered that hatchlings can learn to link a location’s magnetic field with food. Instead of salivating like Pavlovs dogs, the youngsters “dance”, tilting their bodies out of the water, opening their mouths and waving their front flippers. By feeding hatchlings while exposing them to a specific magnetic field, the researchers trained them to dance when they later encountered the same field. “They are very food motivated and eager to dance when they think there is a possibility of being fed”, says Alayna Mackiewicz from the University of North Carolina at Chapel Hill. The team then used this behaviour to test whether turtles were seeing or feeling the magnetic field. They exposed each hatchling to a strong magnetic pulse that temporarily disabled its ability to feel magnetism. If the turtles stopped dancing after the pulse, they were feeling the field; if not, they were using another sense. Training the turtles was demanding. Mackiewicz and Dana Lim spent 2 months feeding 8 hatchlings in the magnetic field found around the Turks and Caicos islands so they would learn to dance in that field. They also trained other youngsters in the magnetic field near Haiti. The researchers then transferred each turtle to a large metal coil that delivered the magnetic pulse. Afterwards, they placed the hatchlings back into the magnetic field they had learned to recognise to see whether they continued dancing. The zapped turtles danced less, showing that they were feeling the magnetic field that tells them their location. The team notes that hatchlings may rely on additional senses to interpret their global magnetic map. They also use another magnetic sense as a compass that points them in the right direction. Together, these senses allow the youngsters to identify where they are and choose a bearing during their migration.