Figure 40.12: Young Loggerhead Sea Turtles Orient to Magnetic Fields as They Travel in a Giant Closed Circle across the Atlantic Ocean and Back Newly hatched loggerhead sea turtles, studied in a pool of water represented by the large tan circles, were exposed to magnetic fields that mimicked Earth’s magnetic field at each of the three red-dotted locations in the ocean. Within each diagram of the pool (each large tan circle), each small dot shows the direction a turtle tried to swim, the solid arrow shows the average swimming direction, and the dashed lines show the 95% confidence limits for swimming direction. The data indicate that as sea turtles travel in the currents of the North Atlantic Subtropical Gyre, they orient relative to local magnetic fields to swim in directions that keep them within the closed circle of current flow.