Loggerhead turtles use geomagnetic field to navigate large distances

The loggerhead turtle can learn and remember the magnetic signature of an area and does a ‘turtle dance’ when in a location that they associate with food, a study in Nature reports. This finding presents strong evidence that turtles can learn to distinguish between magnetic fields, creating an internal ‘magnetic map’. The authors discovered this sense relied on a separate mechanism to the magnetic ‘compass’ of the turtle, implying that turtles have two distinct geomagnetic senses to facilitate navigation. “Conditioned responses in this new magnetic map assay were unaffected by radiofrequency oscillating magnetic fields, a treatment expected to disrupt radical-pair-based chemical magnetoreception, suggesting that the magnetic map sense of the turtle does not rely on this mechanism,” the researchers write. The findings provide evidence that two different mechanisms of magnetoreception underlie the magnetic map and magnetic compass in sea turtles.” The findings suggest that migratory species such as loggerhead turtles use the geomagnetic field as a map when navigating large distances.