Dancing turtles reveal how animals navigate magnetic fields

I can’t imagine what it would be like to sense a magnetic field.

But a new study has presented the first evidence that loggerhead turtles (Caretta caretta) use magnetic fields as a compass to determine direction and also use it to determine their geographical location.

There’s a little dance involved, too.

Sea turtles are extraordinary navigators, able to trace unseen pathways across thousands of kilometres of the ocean and return to the same feeding sites migration after migration.

The discovery is a major advance in the understanding of how animals perceive and use the Earth’s magnetic field. 

Understanding how turtles detect and interpret magnetic fields could help conservationists mitigate disruptions caused by human-made structures that interfere with natural magnetic cues.

It may also contribute to the development of new navigation technologies.

“Our study investigated for the first time whether a migratory animal can learn to recognise the magnetic signatures of different geographic areas,” says Dr Kayla Goforth, first author of the study published in the journal Nature.

“Researchers have speculated for decades that animals can learn magnetic signatures, but this is the first empirical demonstration of that ability, so it fills in an important gap in our knowledge.” 

But what is a “magnetic signature?”

Earth’s magnetic field is present everywhere across the globe, but it isn’t uniform. Several parameters – include its intensity and inclination, the angle formed between magnetic field lines and the surface of the Earth – vary predictably depending on the location.

It is these magnetic signatures which the loggerhead turtles can recognise, learn, and remember.

How do we know?

The researchers conditioned captive juvenile loggerheads over 2 months by feeding them inside a magnetic field adjusted to replicate one found at a real-life oceanic location.

The same animals also spent an equal amount of time in a second magnetic field, where they were not fed.

Four months later, they once again exposed the loggerheads to the 2 magnetic fields and measured the amount of time they spent “turtle dancing”.

Turtle dance behavior. Credit: Goforth, K.M., Lohmann, C.M.F., Gavin, A. et al. Learned magnetic map cues and two mechanisms of magnetoreception in turtles. Nature (2025). https://doi.org/10.1038/s41586-024-08554-y

According to the authors of the study, turtle dance behaviour is: “…a distinctive pattern of movement displayed by captive sea turtles anticipating food.

“Hallmarks of the behaviour include some or all of the following: tilting the body vertically, holding the head near or above water, opening the mouth, rapid alternating movement of the front flippers, and, occasionally, even spinning in place, hence the name ‘turtle dance’,” they wrote in the study.

They found the loggerheads spent significantly more time turtle dancing when exposed to the first magnetic field, compared to the other. And both the inclination and intensity of the magnetic field had to match the rewarded field for the turtles to respond.

The turtles had learned and remembered it as the area where they received food.

This suggests that turtles use learned magnetic information to navigate back to foraging areas.

“The ability to distinguish among magnetic fields of different geographic areas likely explains how many animals – not just sea turtles – can navigate long distances to specific locations,” says Ken Lohmann, a professor of biology at the University of North Carolina at Chapel Hill in the US.

But how do loggerhead turtles sense this magnetic information?

While the mechanisms haven’t been definitively determined in any animal, several have been proposed.

One such mechanism, “chemical magnetoreception”, is thought to be disrupted by oscillating magnetic fields in the radiofrequency range (0.1–10MHz).

While the loggerheads’ ability to orientate themselves using magnetic fields as a compass was disrupted by radiofrequency oscillating magnetic fields, their ability to recognise food-associated magnetic fields was not.

This suggests that the turtles’ magnetic map sense and compass sense rely on 2 different mechanisms.

“We’ve known for 20 years that sea turtles have magnetic maps and now, by showing that they can learn new locations, we have learned how the maps might be built and modified,” says Catherine Lohmann, a professor of biology at UNC-Chapel Hill.

“It is amazing that sea turtles have access to a wealth of invisible information that they use to navigate in ways that are hard for us to even imagine.”