Baby Turtles ‘Read’ Earth’s Magnetic Field

University of North Carolina scientists have found the strongest evidence yet that baby loggerhead turtles “read” the Earth’s magnetic field to help them navigate the massive clockwise current that sweeps the northern Atlantic Ocean.

Small magnetite deposits in the turtles’ brains allow them to recognize magnetic fields that mark geographic regions where they must change direction to stay on course, biologist Kenneth J. Lohman and his colleagues reported in the Oct. 12 Science.

The team tested the turtles in a saltwater-filled pool surrounded by a computerized coil system that reproduced magnetic fields the animals would encounter on their migration. The turtles sensed the fields and changed swimming directions in a way that would have guided them across the ocean.