Turtle Magnetism

WIKIMEDIA, US FISH AND WILDLIFE SERVICEThe magnetic signatures of Florida’s beaches lead loggerhead sea turtles back to their birthplace to hatch the next generation, researchers reported last week (January 15) in Current Biology.

The Earth’s magnetic field is in constant flux, yet the turtles use it to navigate in the open ocean. Until now, however, the turtle’s magnetic senses weren’t explored as a possible explanation for the adult females’ incredible homing ability. J. Roger Brothers and Kenneth Lohmann of the University of North Carolina hypothesized that if the turtles also followed the magnetic field back to their birthing beaches, shifts in the field should impact where on the beach loggerhead mothers-to-be landed. In particular, a change in the distances between the magnetic addresses, or isolines, on the beach would lead to a change in the density of turtle nests.